Correct Answer: D. Antiphospholipid antibody syndrome
Antiphospholipid antibody syndrome (APS) is the most probable diagnosis because this patient presents with the classic obstetric manifestation triad: recurrent first-trimester losses (8 and 11 weeks), second-trimester loss (24 weeks with preterm delivery), and early-onset preeclampsia. The pattern of losses across trimesters with no cardiac activity at 11 weeks suggests placental insufficiency and thrombosis rather than chromosomal abnormality. APS causes thrombophilia affecting placental vasculature, leading to infarction, placental insufficiency, and fetal loss. The diagnosis is supported by the presence of antiphospholipid antibodies (lupus anticoagulant, anticardiolipin, or anti-β2-glycoprotein-I antibodies). Early-onset preeclampsia in APS occurs due to placental ischemia from microvascular thrombosis. According to Indian guidelines (ICOG recommendations) and Harrison, APS accounts for 15–20% of recurrent pregnancy losses. The clinical presentation—multiple losses across trimesters without apparent maternal systemic disease—is pathognomonic for APS. Treatment with low-dose aspirin and low-molecular-weight heparin significantly improves outcomes in subsequent pregnancies.
Why the other options are wrong
A. Syphilis — While syphilis (untreated secondary/tertiary) can cause fetal loss and preterm delivery, it typically presents with hydrops fetalis, hepatosplenomegaly, and stigmata in surviving infants. The pattern of recurrent losses across all trimesters without systemic maternal signs (rash, condylomata, hepatitis) makes syphilis less likely. Syphilis is also screened routinely in Indian antenatal care (NACO guidelines), making undiagnosed infection unlikely in a G4 woman. B. Gestational diabetes mellitus — GDM causes macrosomia, polyhydramnios, and late-pregnancy complications (stillbirth, neonatal hypoglycemia), not recurrent first and second-trimester losses. GDM typically manifests in the third trimester and is associated with large-for-gestational-age infants, not early fetal demise. The absence of maternal hyperglycemic symptoms and the pattern of early losses excludes GDM as the primary diagnosis. C. TORCH infections — TORCH infections (toxoplasmosis, rubella, CMV, HSV) cause congenital infection with organomegaly, microcephaly, and chorioretinitis, not recurrent pregnancy losses. While TORCH can cause fetal loss, it typically presents with single-pregnancy involvement and maternal systemic symptoms (fever, rash, lymphadenopathy). The recurrent pattern across multiple pregnancies without maternal illness is atypical for TORCH; APS is the recurrent thrombotic disorder.
High-Yield Facts
- Obstetric APS criteria: ≥3 consecutive unexplained losses before 10 weeks OR ≥1 loss ≥10 weeks OR ≥1 preterm delivery <34 weeks due to placental insufficiency/preeclampsia.
- Pathophysiology: Antiphospholipid antibodies bind β2-glycoprotein-I, activate complement and tissue factor, causing placental thrombosis and infarction.
- Early-onset preeclampsia (<34 weeks) with recurrent losses is a red flag for APS; occurs in 5–10% of APS pregnancies.
- Treatment: Low-dose aspirin (75–100 mg daily) + low-molecular-weight heparin (LMWH) throughout pregnancy improves live birth rate to >70% in APS.
- Diagnosis: Requires two positive tests for lupus anticoagulant, anticardiolipin IgG/IgM, or anti-β2-glycoprotein-I antibodies, ≥12 weeks apart.
Mnemonics
APS Obstetric Triad RRL-PE: Recurrent first-trimester losses, Recurrent second-trimester losses, Preeclampsia (early-onset). Any two of these three + positive antibodies = APS. Why APS Causes Loss THROMB: Thrombosis in placental vessels → Hemostasis failure → Reduced placental perfusion → Oxygen deprivation → Miscarriage/preterm delivery.
NBE Trap
NBE may pair "recurrent pregnancy loss" with TORCH or syphilis (classic infectious causes) to distract from the thrombotic mechanism unique to APS. The key discriminator is the pattern across all trimesters (not single-pregnancy infection) and early-onset preeclampsia, which are pathognomonic for APS, not infection.
Clinical Pearl
In Indian antenatal clinics, a woman with ≥2 losses and early-onset preeclampsia should trigger immediate APS screening (lupus anticoagulant, anticardiolipin, anti-β2-glycoprotein-I) and initiation of aspirin + LMWH in the next pregnancy—this simple intervention converts a 90% loss rate to >70% live birth rate, making APS one of the few treatable causes of recurrent loss.
_Reference: DC Dutta's Textbook of Obstetrics Ch. 23 (Recurrent Pregnancy Loss); Harrison Ch. 319 (Antiphospholipid Syndrome); ICOG Guidelines on Recurrent Pregnancy Loss_