Antenatal Care

Question 1

What is gravidity?

Answer 1

• how many times a woman has been pregnant
• includes miscarriage, ectopic, termination, live birth, stillbirth, molar pregnancies

Example: Mrs X currently 12/40, two miscarriages at 8/49 and 20/40, one son born at 38/40 → G₄P₁⁺²

Question 2

What is parity?

Answer 2

• how many babies a woman has delivered at 24+ weeks gestation, alive or dead
• pregnancies delivering at <24/40 are denoted by a suffix eg P3⁺²

• Example 1: Ms Y not pregnant, has twins born at 34/40 → G1P2 or G1P1 (twins)*
• Example 2: Miss Z currently 28/40, one prev ectopic, two terminations both at 6/40, one stillbirth due to abruption at 25/40 → G5P1⁺³*

Question 3

What do the terms primigravid, nulliparous and multiparous refer to?

Answer 3

• primigravid → first ever pregnancy ie. G1P0
• nulliparous → has had no delivery of a baby >24/40
• multiparous → has had one or more deliveries of babies >24/40

Question 4

What is the most accurate way to calculate a woman’s gestation?

Answer 4

• all women should now be offered a first timester USS at 11-13/40
• crown rump length (CRL) most accurate way to date a pregnancy
• dating by USS is less accurate beyond this gestation, particularly >20/40
• after this, head circumference and biparietal diameter are used instead of CRL

NB: Nagele’s rule (for 28 day cycle) = LMP - 3months + 1 year+7days

Question 5

NICE issued guidelines on routine care for the healthy pregnant woman in March 2008. They recommend:

• 10 antenatal visits in the first pregnancy if uncomplicated
• 7 antenatal visits in subsequent pregnancies if uncomplicated
• women do not need to be seen by a consultant if the pregnancy is uncomplicated

When is the booking visit and what is its purpose?

Answer 5

• 8-12 weeks (ideally <10)
• general info → diet, alcohol, smoking, folic acid, vit D, antenatal classes
• obs → BP, urine dip, check BMI
• FBC, blood group, rhesus status, red cell alloantibodies, haemoglobinopathies
• hepatitis B, syphilis, rubella
• HIV test offered to all women
• urine culture to detect asymptomatic bacteriuria

Question 6

When is the dating scan?

Answer 6

• 11-13 weeks
• confirm dates + exclude multiple pregnancy

Question 7

When is the combined screening test for Down’s syndrome?

Answer 7

• 11-13 weeks

Question 8

When is the anomaly scan?

Answer 8

• 18-20⁺⁶ weeks
• looks for 11 conditions
• info about anomaly scan given prior at 16 weeks, when blood results also given and iron supplementation considered

Question 9

When is anti-D prophylaxis given to rhesus negative women?

Answer 9

• 1st dose: 28 weeks
• 2nd dose: 34 weeks

the evidence base suggests that there is little difference in the efficacy of single-dose (at 28 weeks) and double-dose regimes (at 28 & 34 weeks). For this reason the RCOG in 2011 advised that either regime could be used ‘depending on local factors’​

Question 10

At 36 weeks, on top of routine care what else should be checked?

Answer 10

• check presentation - offer external cephalic version if indicated
• information on breast feeding, vitamin K, baby-blues

Question 11

What is the relationship between maternal age and Down’s syndrome?

Answer 11

• is a major risk factor for Down’s syndrome
• risk is 2-3% for women over 45 years
• but there are many more pregnancies in younger women
• the risk for an individual is less, but there are more affected babies in younger women
• age alone is ineffective as a screening method

Question 12

What is the combined test for Down’s?

Answer 12

• done @ 11-13⁺⁶ weeks
• recommended for those booking in 1^st trimester
• combines ultrasound (nuchal translucency) and 2 serum markers:
  
  • hCG
  • PAPP-A
• advantages → early result, detection rate (85%), false +ve rate (2.2%)
• if women book later in pregnancy either the triple or quadruple test should be offered
• this tests for Down’s (21), Edward’s (18) + Patau’s (13)

The results of combined test and age of mother are all used by software to calculate high or low risk of having a baby with one of the conditions. Can choose to be screened for just Down’s or all 3; it does NOT tell you if you have it, just the risk. If screening test says you’re low-risk, should be told within 2wks. If high-risk, told within 3 working days.

Question 13

What is the quadruple test and when is it done?

Answer 13

• 14-20 weeks
• 15% of women present after first trimester
• NT unreliable at this stage
• offered serum testing but has lower detection rate (80%) and a higher false positive rate (3.5%) than combined test
• it cheks alpha-fetalprotein (AFP), hCG, unconjugated oestriol and inhibin-A
• combined w/ maternal age to provide individualised risk

Question 14

What does a positive/high-chance combined test result mean?

Answer 14

• risk of 1 in 150 or greater regarded as “positive”
• 1 in 9 turn out to have affected fetus after positive combined screening test
• that means 8 false positives for every 1 true positive
• screen positive women offered CVS or amniocentesis
• CVS performed early (11-14wks) but miscarriage rate 1-2%
• amniocentesis possible from 15wks so later result but miscarriage rate lower at 0.5-1%

Question 15

What happens during chorionic villus sampling (CVS)?

Answer 15

• involves removing + testing sample of cells from placenta
• carried out under guidance of USS
• transabdominal CVS (predominantly) → through tummy, cleaned + local anaesthetic injected into skin; needle inserted through skin into womb + guided to placenta using USS; syringe attached to needle to take small sample of cells
• transcervical CVS → sample of cells collected via cervix; thin tube attached to syringe or small forceps inserted through vagina + cervix and guided towards placenta using USS
• usually takes 10 mins, monitored afterwards for up to an hour, arrange for someone to drive pt home

Question 16

What advice should be given after CVS (as well as amniocentesis), to the woman?

Answer 16

• described as being uncomfortable (rather than painful), may have slightly sore tummy after
• normal to have cramps after, similar to period pain + light PV bleeding (spotting) for a day or two
• can take painkillers such as paracetamol (but NOT iboprufen or aspirin), may wish to avoid strenuous activity for rest of day
• contact midwife or hospital if any of the following develop:
  
  • persistent/severe pain, high temp, chills, shivering, heavy PV bleeding, contractions

This advice is the same as for recovery for amniocentesis too

Question 17

What are the associated risks of having CVS?

Answer 17

• MISCARRIAGE → 1-2% ie. 1-2 women out of a 100 will have a miscarriage after having CVS
  
  • difficult to determine which miscarriages would have happened anyway + which are result of CVS procedure
  • most miscarriages that happen after CVS occur within 3 days of procedure
• INADEQUATE SAMPLE → in around 1% of procedures; may need to be carried out again, or wait to have amniocentesis
• INFECTION → rare; occurs in less than 1/1000
• RHESUS SENSITISATION → if mothers blood type is Rhesus negative but baby’s is RhD positive, it is possible for sensitisation to occur

Question 18

Amniocentesis is similar to CVS but is carried out between the 15th and 20th week.

What happens in amniocentesis?

Answer 18

• take small sample of amniotic fluid so cells can be tested
• USS before + during, allows to check position of baby + find best place to remove some fluid and ensure needle can pass safely through walls of belly + womb
• area cleaned w/ antiseptic solution + local anaesthetic injected into skin to numb area
• using USS, needle passed into amniotic sac + syringe used to remove small sample of fluid:
  
  • in 8/100 women, not enough fluid removed first time so needle inserted again
  • isn’t painful but may feel uncomfortable
• takes around 10 mins + monitored for up to an hour afterwards for SE

Question 19

What are the important risks associated with amniocentesis?

Answer 19

• MISCARRIAGE → estimated to be 0.5-1%; higher risk if carried out before 15wks; most occur within 3days of procedure
• INJURY FROM NEEDLE → placenta may be punctured by needle; sometimes necessary for needle to go through placenta to access amniotic fluid; usually heals without any problems
• INFECTION → lower than 1 in 1000
• RHESUS SENSITISATION → if mother’s blood type RhD negative but baby’s RhD positive

Question 20

What happens if the condition is found (Down’s) following CVS or amniocentesis?

Answer 20

• can speak to specalists → midwife, consultant paediatrician + geneticist
  
  • able to give detailed info about condition, symptoms child may have, treatment + support
• main options are → CONTINUE with pregnancy or TERMINATION
• difficult decision but never alone
• several charities can also offer support + information
  
  • Antenatal Results + Choices (ARC)
  • Down’s Syndrome Association

Question 21

What is non-invasive prenatal testing (NIPT)?

Answer 21

• expensive - costs around £700 privately
• being introduced as second line screen under NHS
• non-invasive: detects cell-free foetal DNA in maternal circulation
• sensitivity 99% for Down’s + 97% for Edward’s
• occasionally no free DNA detected + test repeated
• remains a screening test
• higher sensitivity + specificity reduced need for CVS/amniocentesis

Question 22

What are common teratogenic drugs?

Answer 22

• ACE inhibitors
• acne meds: isotretinoin/accutane
• alcohol
• androgens
• tetracyclines + doxycycline
• warfarin
• anticonvulsants
• lithium
• methotrexate
• carbimazole
• cocaine
• thalidomide

Question 23

What are the teratogenic effects of specific anticonvulsants in pregnancy?

Answer 23

• sodium valproate → neural tube defects
• carbamazepine → least teratogenic of older antiepileptics
• phenytoin → cleft palate
• lamotrigine → safe?

Question 24

What happens in a rhesus negative pregnancy?

Answer 24

• along w/ ABO system, the rhesus system is the most important antigen found on RBCs
• the D antigen is the most important antigen of the rhesus system
• around 15% of mothers are rhesus negative (Rh -ve)
• if a Rh -ve mother delivers a Rh +ve child, a leak of foetal red blood cells may occur
• this causes anti-D IgG antibodies to form in mother
• in later pregnancies, these can cross placent and cause haemolysis
• this can also occur in first pregnancy due to leaks

Question 25

What is the **prevention** for Rhesus disease?

Answer 25

* test for D antibodies in all Rh -ve mothers at **booking** * NICE (2008) advise giving anti-D to non-sensitised Rh -ve mothers at **28** and **34** weeks * **anti-D prophylaxis** (prevents sensitisation) - once sensitisation has occured it is irreversible * the exogenous anti-D '**mops up**' foetal RhD and prevents sensitisation; only used if mother not already producing antigens * if event is in 2nd/3rd trimester give large dose of anti-D + perform Kleihauer test → determines proportion of foetal RBCs present

Question 26

What is the **management** of Rhesus iso-immunisation?

Answer 26

* **identification** → screen for unsensitised women at 28; antibody testing + obstetric history * **assess severity of foetal anaemia** → done using doppler USS * **treatment in utero** → transfusion into umbilical vein if severe, or if \>36 weeks deliver * **monitor** → neonatal FBC + LFTs All babies born to Rh -ve mother should have cord blood taken at delivery for FBC, blood group + direct Coombs test. Coomb's test: direct antiglobulin - will demonstrate antibodies on RBCs of baby.

Question 27

In what situations should anti-D immunoglobulin be given **as soon as possible** (/always \<72hrs)?

Answer 27

* delivery of **Rh +ve** infant, whether live or stillborn * any **ToP** * **miscarriage** _if gestation \>12wks_ * **ectopic pregnancy** (if managed _surgically_, if managed medically with methotrexate then anti-D not required) * **external cephalic version** * **antepartum haemorrhage** * **amniocentesis, chorionic villus sampling, foetal blood sampling** * abdominal **trauma** Anti-D needs to be given because these are all _sensitising events_!

Question 28

**Rhesus**: How will the **affected foetus** present?

Answer 28

* oedematous (hydrops fetalis, as liver devoted to RBC production albumin falls) * jaundice, anaemia, hepatosplenomegaly * heart failure * kernicterus Rx → **transfusions + UV therapy**

Question 29

How is **polyhydramnios** detected?

Answer 29

* increased **symphysiofundal height** * tense cystic uterus; foetal parts hard to feel * **amniotic fluid index** (AFI) * ultrasound 4 quadrants: for each measure depth of deepest unobstructed pool; sum of 4 measurements * _total_ of 8-18cm is normal; **\>24cm** is polyhydramnios * or _single_ pool of more than **8cm**

Question 30

What are the **causes** of polyhdramnios?

Answer 30

**DITCH** * **D**iabetes * **I**diopathic (60%) * **T**wins * **C**ongenital abnormalities * **H**eart failure

Question 31

What are the **risks** of polyhydramnios?

Answer 31

Ps * Placental abruption * Pretty unusual lie * Premature labour * Prolapse of cord * Post-partum haemorrhage * Perinatal mortality

Question 32

NICE published guidance in 2010 on the management of **hypertension** in **pregnancy**. They also made recommendations on reducing the risk of hypertensive disorders developing in the first place. **Who** are the women at risk of developing pre-eclampsia and **what** should they take?

Answer 32

* **E**xisting chronic hypertension * **C**hronic kidney disease * **L**upus (SLE) * **A**ntiphospholipid syndrome * **M**aternal diabetes (pre-existing, not GD) * **P**revious pregnancy w/ HTN * **O**besity Give **aspirin 75mg** od from _12/40_

Question 33

The classification of hypertension in pregnancy is complicated and varies. How does the pattern of blood pressure **change** in the **first trimester** (of a normal pregnancy)?

Answer 33

* BP usually **falls** in first trimester (particularly _diastolic_) * continues to fall until **20-24 weeks** * after this, BP usually **increases** to _pre_-pregnancy levels by term

Question 34

What are the **three categories** of hypertension in pregnancy?

Answer 34

Question 35

What is the **treatment** for hypertension in pregnancy?

Answer 35

* prevents development of severe HTN **\>160/100** * reduces risk of stroke * **labetalol** first line * **nifedipine**, **hydralazine** or **methyldopa** second line * not ACEI (risk of congenital malformations) + not diuretics (reduce maternal plasma volume)

Question 36

What is **pre-eclampsia** (PET)?

Answer 36

* pre-eclampsic toxaemia * disease of placenta: resolves _after_ delivery * affects 5% of pregnancies * onset after **20 weeks** * **_hypertension**_ + _**proteinuria_** ⇒ gestational proteinuric hypertension * **non-dependent oedema** (variable oedema of hands, face, ankles)

Question 37

How is a **diagnosis** of pre-eclampsia made?

Answer 37

* hypertension **\>140/90** on more than one occasion * AND proteinuria **\>0.3g / 24hrs** * equiv to protein creatinine ratio of 30mg/mmol * approx equivalent to 2+ on urine dip * in absence of urinary tract infection Other features that may indicate severe PET: **headache, visual disturbance, papilloedema, RUQ/epigastric pain, hyperreflexia, low platelets, abnormal LFTs, HELLP syndrome**

Question 38

What is the **pathophysiology** of pre-eclampsia?

Answer 38

Question 39

What are **foetal** **complications** of PET?

Answer 39

* foetal growth restriction * intra-uterine death * premature delivery (iatrogenic)

Question 40

What are **maternal complications** of PET?

Answer 40

* **S**troke * **H**ELLP syndrome * **A**bruption of placenta * **M**ulti-organ failure (+/- DIC +/- Death) * **E**clampsia

Question 41

What is **HELLP** syndrome?

Answer 41

* **H**aemolysis * **E**levated **L**iver enzymes * **L**ow **P**latelets

Question 42

What is the treatment for pre-eclampsia (as prev mentioned as well)?

Answer 42

* antihypertensives → **labetalol** * admit to hospital for monitoring * VTE prevention * **delivery** is only definitive cure for PET

Question 43

What are the key **red flag signs and symptoms** to ask about for pre-eclampsia?

Answer 43

* headache * visual disturbance * epigastric/RUQ pain (hepatic capsule distension or infarcts) * breathlessness (pulm oedema due to ARDS) * peri-orbital oedema * hyper-reflexia * clonus

Question 44

What needs to be **monitored** in a pre-eclamptic woman?

Answer 44

* **symptoms** + **BP** * ultrasound for **foetal growth** * umbilical artery blood flow (correlates w/ placental resistance) * pre-eclampsia bloods * **FBC** → low platelets? * low **Hb** due to haemolysis in HELLP * **U+Es** → raised urea + creatinine * **LFTs** → raised AST + ALT ("transaminitis"); raised bilirubin if haemolysis

Question 45

What is the **timing of delivery** in pre-eclampsia?

Answer 45

* aim for best chance of foetal survival ie. **34 weeks or later** if possible * use **maternal steroids** up to 36 weeks * delay delivery by 24hrs for maternal steroid injection reduces foetal mortality by 50% * reduces risk of foetal: intraventricular haemorrhage, resp distress and necrotising enterocolitis * high BP, impaired renal or hepatic function and foetal distress may prompt early delivery

Question 46

What is the _emergency management_ for **eclampsia**?

Answer 46

* **ABC** - may need oxygen, intubation * manual uterine displacement (MUD) or turn patient onto her side (to reduce risk of aspiration + prevent aorto-caval compression) * control fits → **IV magnesium sulphate** * control HTN → **IV labetalol** or **hydralazine**

Question 47

Diabetes in pregnancy can lead to significant maternal and foetal morbidity and mortality. The risks can be significantly reduced by optimising control. Pregnancies need to be treated as high risk and closely monitored. What are the **diabetic risks** in pregnancy?

Answer 47

* **S**houlder dystocia * **M**acrosomia * **A**mniotic fluid XS * **S**tillbirth * **H**ypertension + neonatal hypoglycaemia \*Plus congenital abnormaltiies and miscarriages in pre-existing diabetes but NOT gestational diabetes!

Question 48

What is the **pre-conception advice** for pre-existing diabetes for pregnancy?

Answer 48

* impact on pregnancy starts from pre-conception * high dose **folic acid** (5mg daily) from pre-conception * don't stop contraception until good control achieved (ideally HbA1c **_\<_48mmol/mol**) * avoid pregnancy if poor control (**HbA1c \>86mmol/mol**) as v high risk of congenital malformations * monitor eyes + renal fxn carefully before and during pregnancy * diagnosis will *usually* be already made * suspect if persistent glycosuria in **first trimester** + high random blood sugars on testing * confirmed w/ oral glucose tolerance test * **first trimester presentation suggests pre-existing diabetes**

Question 49

What are the **effects** of pregnancy on **pre-existing diabetes**?

Answer 49

* **increased insulin requirement** (insulin resistance increases in pregnancy) * acceleration of **retinopathy** * deterioration in renal fxn if pre-existing nephropathy - can manifest as HTN * **maternal hypoglycaemia** in early pregnancy

Question 50

What are the principles of **management** in pre-existing diabetes?

Answer 50

* **pre-conceptual counselling** - improved control reduces risk * manage w/ **diabetes team** - alter meds to optimise control * stop metformin, commence insulin * _stop_ ACEi + statins * screen for + monitor vascular complications * aspirin 75mg/day from 12wks to birth * **early viability scan at 8 weeks + detailed anomaly scan + regular growth scans**

Question 51

**Gestational diabetes** is diabetes with onset _during_ pregnancy. Unlikely to impact on pregnancy until **2nd trimester**. No macro- or microvascular complications. Increased glucose load combined with increased insulin resistance pushes body into a *temporary* diabetic state. There is increased risk of subsequent GD + T2DM. What are **risk factors** _for_ gestational diabetes?

Answer 51

* BMI of \> 30 kg/m² * prev macrosomic baby weighing 4.5kg+ * prev gestational diabetes * first-degree relative w/ diabetes * family origin w/ high prevalence of diabetes (South Asian, Black, Caribbean, Middle Eastern) ## Footnote ***\*These are also factors for screening***

Question 52

What is the **pathophysiology** of gestational diabetes?

Answer 52

*Pregnancy is a diabetogenic state*

Question 53

What is the **screening** for gestational diabetes?

Answer 53

* Women who've **previously** had gestational diabetes → **OGTT** ASAP after booking + at 24-28 weeks if first test normal. NICE also recommend that early **self-monitoring** of blood glucose is an alternative to OGTTs * Women w/ any of other risk factors should be offered OGTT @ 24-28weeks **OGTT**: fasting venous plasma glucose measured → 75g oral glucose load administered → venous plasma glucose measured at 2hrs *NB. HbA1c not used for diagnosis of diabetes in pregnancy*

Question 54

What are the **diagnostic thresholds** for gestational diabetes?

Answer 54

Question 55

What is the **management** of gestational diabetes?

Answer 55

* newly diagnosed women to be seen in joint diabetes + antenatal clinic within a week * target cap glucose **\<5.3 mmol/l fasting** and **\<7.8mmol/l 1hr after food** * check targets every 2wks * if fasting plasma glucose \<7mmol/l a trial of **diet** + **exercise** offered * if glucose targets not met within 1-2ws of altering diet/exercise → _add_ **metformin** → then _add_ insulin * if at time of diagnosis **fasting glucose \> 7mmol/l** → **insulin** _straight away_ * if plasma glucose between 6-6.9mmol/l + **complications** (macrosomia, hydramnios) → insulin _straight away_ * **glibenclamide** only for those who cannot tolerate metformin + those who fail to meet glucose targets w/ metformin but decline insulin * treatment discontinued after **delivery** * if large for gestational age → consider C-section * if not, plan induction for 38-40wks * be alert for possible **shoulder dystocia** * fasting glucose @ **6wks postpartum** to exclude underlying DM

Question 56

What is **antepartum haemorrhage**?

Answer 56

* **bleeding** in pregnancy _after_ **24weeks gestation** * bleeding at \<24weeks is known as threatened miscarriage

Question 57

What are **causes** of antepartum haemorrhage?

Answer 57

* **UTERINE**: * placental _abruption_ (premature separation) * placenta _praevia_ * vasa praevia (rare) * marginal bleed (bleeding from placental edge) * **CERVICAL**: * 'show' → loss of mucus plug from cervix * cervical cancer * cervical polyp or ectropion * **VAGINAL:** * trauma or infection

Question 58

**Placental abruption** is _premature separation of the placenta from the uterus_. Occurs in approx 1% of pregnancies. **Risk factors** include smoking, prev abruption, hypertensive disorders, thrombophilias, cocaine and trauma. What are the **clinical features** of placental abruption?

Answer 58

* vaginal **bleeding** (often present but not always, can be concealed) * blood can be altered/**_dark red_** as takes time to track out of vagina * abdominal **_pain_** * uterine contractions * shock (in severe cases) * uterine tenderness + 'woody' hard uterus * foetal distress

Question 59

**Placenta praevia** is a placenta that is wholly or partially implanted in the lower segment of the uterus. It affects 0.5% of pregnancies at term. What are the **features** of placenta praevia and what should be **avoided**?

Answer 59

* typically causes **_painless bright red vaginal bleeding_** * blood on toes (usually indicates significant blood loss) * severe bleeds ⇒ hypovolaemic **shock** * foetus relatively unaffected unless massive haemorrhage * women w/ placenta praevias who bleed often advised to remain **inpatient** until delivery * _major_ placenta praevias: delivery by **C-section** @ 39wks (or before if significant bleed) * **_avoid internal examination until placental site has been determined_** - may precipitate heavier bleed in placenta praevia

Question 60

What is the **general management** of antepartum haemorrhage?

Answer 60

* consideration of foetal wellbeing is **secondary** to maternal resuscitation * **CTG** may be appropriate * if baby is of viable gestation **continous** **monitoring** recommended once mother is stable * delivery to save mother's life is also sometimes considered → *emptying womb* improves maternal condition