Fetal complications of pregnancy

Question 1

Growth disorders

Answer 1

If fundal ht differs by 3cm or more, get an U/S

Question 2

SGA

Answer 2

< 10th %ile
Symmetric = think early insult
Asymmetric = think later
Skull > rest of body

Question 3

Decreased growth potential

Answer 3

Trisomies, Turner, OI (osteogenesis imperfect), achondroplasia, NTDs, anencephaly, or intrauterine infections like CMV / rubella, or teratogens like chemo

Question 4

IUGR:

Answer 4

Generally asymmetric (not enough nutrients getting across)

A/w smoking, antiphospholipid Ab, SLE, malnutrition, severe chronic renal dz, HTN, anemia in mom, or placental insufficiency (previa / marginal insertion / thrombosis +/- infarction), or multiples

Check cord doppler to see how placenta’s doing

Question 5

Twin-twin transfusion should be suspected if

Answer 5

One big, one small twin

Question 6

Monitor SGA with fetal testing

Answer 6

NST/OCT (oxytocin challenge test), BPP, and/or umbilical doppler

Question 7

LGA

Answer 7

> 90th %ile

Question 8

Macrosomia

Answer 8

= birth wt > 4,500g officially, but some use other definitions - e.g. to offer C/S if 3500g in diabetic mom, or 4000g otherwise

Question 9

Risks of macrosomia

Answer 9

Big risk shoulder dystocia, brachial plexus injuries, low Apgars, hypoglycemia, polycythemia, hypoCa, jaundice; also childhood leukemia, Wilms tumor, osteosarcoma

Question 10

Macrosomia is associated with

Answer 10

Maternal obesity, gDM or cDM, postterm, multiparity, AMA

Question 11

Amniotic fluid disorders:

Answer 11

Max volume 800mL @ 28wks, then falls to 400mL by 40wks

AFI normal range: 5 to 20-25 (varies by EGA)

Question 12

Oligohydramnios: Definition

Answer 12

AFI < 5

Question 13

Oligohydramnios: Presenting symptoms

Answer 13

See nonreactive NST, FHR decels, meconium

Can lead to cord compression!

Question 14

Oligohydramnios: Etiology

Answer 14

Not making (GU disorders: renal agenesis, polycystic kidney, obstruction; also chronic uteroplacental insufficiency) or losing too much (ROM) amniotic fluid.

Question 15

Oligohydramnios: Management

Answer 15

Check BPP, cord doppler, U/S for anomalies
Induce if ROM at term
Can do amnioinfusion to decrease # of variable decels / “dilute meconium”

Question 16

● Polyhydramnios: Definition

Answer 16

AFI > 20-25

Not as worrisome.

Question 17

Polyhydramnios: Etiology

Answer 17

Not swallowing (GI tract abnormality, duodenal atresia), or making too much (infants of diabetic mothers → osmotic diuretic; or high-output cardiac failure / TTTS- twin twin transfusion syndrome)

Question 18

Polyhydramnois: risk

Answer 18

Risk of cord prolapse

Only AROM if sure that head is engaged; check for cord after SROM

Question 19

Rh incompatibility Management

Answer 19

All this applies to Rh negative moms only
RhoGAM (anti-D IgG)
If already sensitized, follow with middle cerebral artery dopplers (faster = more anemic); (spectrophotometer is another way, older)
Can do PUBS (Percutaneous Umbilical Cord Blood Sampling) / in utero transfusion if really anemic

Question 20

When to give RhoGAM

Answer 20

At 28 wks
Postpartum if neonate is Rh positive
Any time there’s bleeding!

Question 21

What is the dose of RhoGAM?

Answer 21

0.3mg = 1 dose

Question 22

How much fetal RBCs dose one dose of RhoGAM eradicate?

Answer 22

1 dose = eradicates 15 mL fetal RBCs. Good enough for normal delivery
Can do Kleihauer-Betke to quantify if abruption, antepartum bleeding

Question 23

Hydrops

Answer 23

Erythroblastosis fetalis
Heart failure, diffuse edema, fluid in 2+ compartments (ascites /pleural / pericardial effusions), all 2/2 anemia. Jaundice / neurotoxic effects of bilirubin too, but only after delivery (placenta clears it during pregnancy)

Question 24

Other causes of hydrops

Answer 24

Manage all with antibody titers, amnio, MCA doppler, PUBS / transfusion

Kelly kills = anti-Kell1 = hydrops
Duffy dies = anti-Duffy = hydrops
Lewis lives = anti-Lewis = cause mild hemolytic anemia
ABO causes mild hemolysis too

Question 25

Fetal demise Dx

Answer 25

If no explanation, usually attributed to a “cord accident” Dx: lack of uterine growth, falling hCG, U/S (<20wks) or lack of fetal movement (> 20 wks)

Question 26

Fetal demise risk after 3-4 weeks

Answer 26

If > 3-4 wks, can lead to hypofibrinogenemia 2/2 release of thromboplastic substance from decomposing fetus, and even to DIC! so get a fibrinogen level!

Question 27

Fetal demise & multiples:

Answer 27

If one baby dies in utero, check fibrinogen level qweek / biweekly, esp if unusual bleeding (fibrinogen may decrease → coagulopathy!)

Question 28

Spalding sign

Answer 28

Overlapping of fetal skull bones suggesting fetal demise

Question 29

Tx of fetal demise

Answer 29

D&E if early, or induction of labor (prostaglandins / high dose oxytocin) if late.

Question 30

Work up after fetal demise

Answer 30

Test for TORCH, fetal karyotype, screen for collagen vascular dz / coagulopathies, get fetal autopsy

Question 31

Postterm pregnancy:

Answer 31

> 42 wks. Get a nst at 40 and 41 weeks - don't just send home!

Question 32

Risks of postterm pregnancy

Answer 32

Higher risk to mom & baby | Macrosomia, oligo, meconium aspiration, intrauterine demise, dysmaturity syndrome - look like old man!

Question 33

#1 cause of postterm pregnancy

Answer 33

Inaccurate dating

Question 34

Management of postterm pregnancy

Answer 34

Manage with more frequent visits, fetal testing (NST in wk 40, BPP & NST in 2 visits in wk 41) Induce if nonreassuring testing or electively if Bishop > 6 @ wks 40-41; or no matter what > 42

Question 35

Risk of multiples:

Answer 35

Higher risk preterm delivery, congenital abnormalities, SGA, malpresentation.

Question 36

Twins delivery

Answer 36

Usually wks 36-37 Push up testing too Twin delivery: Can do TOL if vtx/vtx or vtx/breech if twins concordant / presenting twin is larger & vtx (grab smaller second twin & pull out breech!)

Question 37

Triplets delivery

Answer 37

Usually wks 33-34 Push up testing too! Triplet delivery: only if vtx/vtx/vtx (rare), usually C/S. Also C/S for more than 3.

Question 38

Dizygotic twins:

Answer 38

2 ova, 2 sperm. increased FSH can be hereditary, so dizygotic twins can be too

Question 39

Monozygotic twins:

Answer 39

Division of fertilized egg

Question 40

Dichorionic / diamniotic

Answer 40

DiDi if divides on days 1-3 All dizygotic twins are DiDi Monozy twins can be whatever DiDi: best outcome See twin peak sign later in pregnancy

Question 41

Monochorionic / diamniotic

Answer 41

MoDi if divides on days 4-8 See two amniotic sacs, one chorion early on U/S. Risk TTTS (twin twin transfusion syndrome)

Question 42

Monochorionic / monoamniotic

Answer 42

MoMo if divides on days 8-13 | Risk conjoinment, fetal death 2/2 cord entanglement, etc.

Question 43

Conjoined

Answer 43

Conjoined if divides on days 13-15

Question 44

Selective reduction

Answer 44

Can consider selective reduction if triplets or above

Question 45

Twin-twin transfusion syndrome (TTTS, aka poly-oli sequence)

Answer 45

One small, oligohydramnios, growth restriction, anemia twin (donor), large, plethoric, hypervolemic, cardiac failure, polyhydramnios polycythemic / hydropic twin (recipient)

Question 46

Dx of TTTS

Answer 46

Dx with ultrasound, historically managed with serial amnioreduction, but now laser coagulation of artery by fetal surgeons improves outcomes.