Large for Dates Pregnancy

Question 1

Occurrence of large for dates pregnancy?

Answer 1

Very common reason for USS referral from midwife; the symphisis-fundal height is greater than the gestational weeks

Question 2

Common reasons for a large for dates pregnancy?

Answer 2

Wrong dates - often occurs with late bookers, i.e: women who present after the 1st trimester:
• Concealed pregnancy
• Vulnerable women, e.g: learning disability
• Booked abroad

Foetal macrosomia

Polyhydramnios

Diabetes

Multiple pregnancy

Question 3

What is foetal macrosomia?

Answer 3

A big baby (this can be be normal or it can be a sign of pathology)

Question 4

Determining that foetal macrosomia is present?

Answer 4

USS - foetal weight will be >90th centile

This can be used with customised growth charts, which consider ethnicity, BMI and parity

Question 5

Consequences of diagnosing foetal macrosomia?

Answer 5

Maternal and clinician anxiety

Labour dystocia (AKA obstructed labour) - defined as difficult or abnormally slow labour; in the case of foetal macrosomia, it is because the baby is too large for the pelvis

Shoulder dystocia

Post-Partum Haemorrhage (PPH)

Question 6

Alternative terminology related to labour dystocia?

Answer 6

Inefficient uterine contractions

Failure to progress

Protracted or arrested labor,

Prolonged labor

Dysfunctional labor

Protracted or arrested descent

Cephalopelvic disproportion

Question 7

Management of foetal macrosomia?

Answer 7

EXCLUDE DIABETES (the most common cause)

Reassure mother

Consider delivery method:
• Conservative
• Induction of Labour (IOL)
• C/S (caesarian section)

Question 8

What is polyhydramnios?

Answer 8

Excess amniotic fluid

Question 9

Causes of polyhydramnios?

Answer 9

Maternal diabetes (most common cause)

Foetal anomalies - amniotic fluid amount is determine by the balance between the foetus swallowing fluid and how much they urinate; if, e.g: foetus cannot swallow due to atresia, this can lead to excess fluid

Monochorionic twin pregnancy - consider twin-twin transfusion syndrome (TTTS)

Hydrops fetalis - serious foetal condition defined as abnormal accumulation of fluid in ≥2 foetal compartments, inc. ascites, pleural effusion, pericardial effusion and skin oedema; it can be assoc, with polyhydramnios

Question 10

Potential causes of hydrops fetalis?

Answer 10

Can be idiopathic

Rhesus isoimmunisation

Infection, e.g: with erythrovirus B19 (parvovirus)

Question 11

Clinical features of polyhydramnios and potential consequences?

Answer 11

Abdominal discomfort

Prelabour membrane rupture

Pre-term labour (due to over-distension of the uterus)

Cord prolapse (obstetric emergency)

Question 12

Diagnosis of polyhydramnios?

Answer 12

Clinical:
• Large for Dates (LFD) on abdominal examination
• Malpresentation
• Tense, shiny abdomen
• Inability to feel foetal parts (due to fluid)

USS:
• Amniotic Fluid Index (AFI) > 25
• Deepest Vertical Pool (DVP) > 8cm

Question 13

Ix for polyhydramnios?

Answer 13

Oral Glucose Tolerance Test (OGTT) - check for diabetes

Serology on maternal blood:
• Toxoplasmosis
• CMV
• Parvovirus

Antibody screen

USS - do a foetal survey, checking the lips and stomach of the foetus for abnormalities, e.g: if stomach is distended, consider duodenal atresia

Question 14

Mx of polyhydramnios?

Answer 14

Educate patient on complications and on what they should do:
• Cord prolapse - call ambulance
• Preterm labour
• PPH

Serial USS - check foeal growth, LV and presentation (cannot assume normal cephalic position)

IOL by 40 weeks

Neonatal examination for foetal anomalies

Question 15

What is a multiple pregnancy?

Answer 15

Presence of >1 foetus, i.e: twins, triplets, etc

There is an increased risk to the mother and baby

Question 16

Incidence of multiple pregnancy?

Answer 16

Spontaneous twins - 1 : 80

Spontaneous triplets - 1 : 10,000

The frequency increases with ASSISTED CONCEPTION

Question 17

Risk factors for multiple pregnancy?

Answer 17

Assisted conception, e.g: clomid, IVF

African ethnicity

Geography - Nigeria has a high incidence

FH of multiple pregnancy

Increasing maternal age

Increasing parity, i.e: likelihood increases with subsequent births

Tall women more likely to have multiple pregnancy than short women

Question 18

Define zygosity?

Answer 18

Monozygous - splitting of a single, fertilised egg (30%)

Dizygous - fertilisation of 2 ova by 2 spermatozoa (70%)

Question 19

Define chorionicity?

Answer 19

Either 1 placenta (monochorionic) OR 2 placentas (dichorionic)

NOTE:
• Dizygous twins are always DCDA (dichorionic, diamniotic)
• Monozygous twins can be MCMA, MCDA, DCDA or conjoined, depending on the time at which the fertilised ovum splits

Question 20

Depending on the time, what is the result of the fertilised ovum splitting?

Answer 20

DCDA - if the egg splits at days 1-3; this is the best medical outcome

MCDA - if the egg splits at days 4-8

MCMA - if the egg splits at days 8-13; these twins can be difficult to assess and should be delivered via c/s

Conjoined twins - if the egg splits at days 13-25

Question 21

Methods of determining chorionicity?

Answer 21

USS - look at the shape ???:
• If λ (lambda) sign - DCDA
• If T-sign - MCDA

NOTE - if the twins are different foetal sexes, this makes them DCDA

Question 22

Symptoms of multiple pregnancy?

Answer 22

Exaggerated pregnancy symptoms, e.g:

• Hyperemesis gravidarum (due to the very high levels of β-HCG)

Question 23

Signs of multiple pregnancy?

Answer 23

High alfafetoprotein (AFP)

Large for Dates uterus

Multiple foetal poles

Question 24

When can multiple pregnancy usually be confirmed?

Answer 24

USS confirmation at 12 weeks - check for the λ-sign or T-sign

NOTE - it is very common to miscarry one of the twins (AKA vanishing twin syndrome), as nature gives preference to pregnancies with only 1 foetus

Question 25

Complications of multiple pregnancy?

Answer 25

Perinatal mortality if 6x higher than for singleton pregnancies Foeal: • Congenital anomalies • IUD • Preterm birth due to uterine over-distension • PPH • Growth restriction (can be for both twins or may be discordant) • Cerebral palsy (8x higher risk with twins and 47x higher risk with triplets) • Twin-Twin Transfusion Syndrome (TTTs) ``` Maternal: • Hyperemesis gravidarum • Anaemia • Pre-eclampsia • Antepartum haemorrhage - can occur due to abruption, placenta praevia, etc • Preterm labour • Caesarian section ```

Question 26

What is TTTS?

Answer 26

Vascular anastasmoses between the placentae of MONOCHORIONIC TWINS, results in one of the babies acting as a blood donor to its twin Result is: • 1 foetus that is anaemia and growth-restricted • 1 foetus that is polycythaemic and macrosomic; also has a risk of developing hyrops

Question 27

What is placental abruption?

Answer 27

Separation of a normal situated placenta

Question 28

What is placenta praevia?

Answer 28

Low implantation of the placenta in the uterus, causing it to lie alongside or in front of the presenting part

Question 29

Antenatal management of multiple pregnancy?

Answer 29

USS regularly: • If monochorionic, scan every 2 weeks • If dichorionic, scan every 4 weeks • Anomaly USS at 18-20 weeks Fe supplementation Low-dose aspirin (lower risk of pre-eclampsia) Folic acid (prevent neural tube defects) Encourage smoking cessation

Question 30

Delivery methods with multiple pregnancy?

Answer 30

If DCDA, deliver at 37-38 weeks If MCDA, deliver at 36 weeks Generally, if the 1st twin is in the cephalic position, proceed with vaginal delivery; the 2nd twin can change position If triplets, or more, do c/s

Question 31

Management of labour of multiple pregnancy?

Answer 31

Epidural analgesia USS and FSE (for foetal monitoring); also, use USS to confirm presentation Syntocin is given after delivery of twin 1 NOTE - the inter-twin delivery time should be <30 minutes

Question 32

Types of diabetes in pregnancy?

Answer 32

Pregestational diabetes (PGD): • T1DM • T2DM • MODY Gestational diabetes (GDM) - carbohydrate intolerance leads to hyperglycaemia .......

Question 33

Risks, with pregestational diabetes, in pregnancy?

Answer 33

Congenital anomalies (related to the higher HbA1c) Miscarriage IUD NOTE - in women of reproductive age, with diabetes, ensure contraception

Question 34

Risks assoc. with both pregestational and gestational diabetes in pregnancy?

Answer 34

Pre-eclampsia Polyhydramnios Macrosomia Shoulder dystocia Neonatal hypoglycaemia

Question 35

Why does neonatal hypoglycaemia occur?

Answer 35

If the mother is diabetes, with hyperglycaemia, the baby produces more insulin When delivered, the baby retains these high insulin levels in a low glucose environment

Question 36

Requirements for women with diabetes wishing to become pregnant?

Answer 36

Pre-pregnancy counselling, advice about diabetes and HbA1c monitoring Stopping any embryopathic medications Early booking scan HIGH-DOSE FOLIC ACID (5 mg) - given for 3 months pre-conception until 12 weeks of pregnancy Low dose aspirin (75mg) Foetal anomaly scan at 18 weeks Regular eye checks, for retinopathy, and checks for nephropathy Continuous glucose monitoring (used for T1DM patients) Growth scans, 4 weekly, from 28 weeks NOTE - otherwise, contraception

Question 37

Risk factors for gestational diabetes (GDM)?

Answer 37

Obesity (BMI >30) FH (in a 1st degree relative) Ethnic variation Previous big baby Polyhydramnios If big baby on USS (check abdominal circumference and estimated foetal weight) Glycosuria on urinalysis: • 1+ on >1 occasion of dipstick • 2+ on 1 occasion of dipstick

Question 38

Why do pregnant women develop GDM?

Answer 38

Pregnancy is a diabetogenic state, due to the placental hormones causing insulin resistance Results in overgrowth of insulin-sensitive tissues

Question 39

Issues assoc. with diabetes during pregnancy?

Answer 39

Macrosomia (due to overgrowth of insulin-sensitive tissues) Hypoxaemia in-utero Short-term metabolic complications Foetal metabolic reprogramming, in response to maternal diabetes, leads to long-term risks of: • Obesity • •

Question 40

Screening for and diagnosis of gestational diabetes?

Answer 40

Risk factor screen If patient has previously had GDM: • Blood glucose monitoring • OGTT in 1st trimester; if this is normal, repeat OGTT at 24-28 weeks If patient has never had GDM: • OGTT at 24-28 weeks

Question 41

Procedure of OGTT?

Answer 41

Check the venous fasting blood glucose, i.e: the patient must have fasted Give 75g glucose Check 2 hour venous glucose

Question 42

Results of OGTT?

Answer 42

According to SIGN guidelines (different in England), either/or of the following means the patient has gestational diabetes: • Fasting BG ≥5.1 mmol/l • 2 hour BG ≥8.5 mmol/l NOTE - this is stricter than for diagnosis of non-gestational diabetes

Question 43

Maternal education with GDM diagnosis?

Answer 43

DIET AND EXERCISE (1st line treatment) Caution on assoc. risks, e.g: macrosomia. neonatal hypoglycaemia Increased risk of developing T2DM following pregnancy, as high as 70%; mothers require a fasting blood glucose at 6-8 weeks post-natal Emphasise important of glycaemic control

Question 44

Monitoring of GDM?

Answer 44

Mother should monitor BG at least 4x per day (pre-meal and before bed; sometimes, request a 1 hour post-meal reading); parameters are: • Fasting BG 3.5 - 5.9 mmol/l • 1 hour after meals <7.8 mmol/l

Question 45

Treatment of GDM?

Answer 45

DIET AND EXERCISE (1ST LINE) If this fails to achieve glycaemic control, consider hypoglycaemic drugs: • Metformin • Insulin - short-acting, long-acting or pump NOTE - pump is mainly only for T1DM patients

Question 46

Advantages of metformin in pregnancy?

Answer 46

No risk of hypos Less weight gain Less education required to ensure safety, efficacy and administration, compared to insulin

Question 47

Does insulin cross the placenta?

Answer 47

It does not cross the placenta

Question 48

Disadvantages of insulin in pregnancy?

Answer 48

Can cause hypos More education required

Question 49

Timing of delivery if the mother has pregestational diabetes?

Answer 49

Aim for delivery at or onwards of 38 weeks If on insulin, 38 weeks If on metformin, 39-40 weeks If diet alone, 40-41 weeks NOTE - should deliver by 41 weeks

Question 50

Choosing the mode of deliver with diabetes?

Answer 50

Based on maternal preference If baby is >4.5kg, recommend c/s