Singleton pregnancy losses before gestational week 22 among patients with autoimmune disorders and methylenetetrahydrofolate reductase polymorphisms

Abstract

Background: The rates of pregnancy losses (PLs) are increased by maternal risk factors such as autoimmune disorders (AD) and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms.

Objective: To evaluate singleton PLs before gestational week (gw) 22 among patients with AD and MTHFR polymorphisms.

Methods: Totally, 1108 singleton pregnancies in 243 women were categorized as: 1) 148 pregnancies in 33 patients with AD, 2) 316 pregnancies in 66 patients with MTHFR polymorphisms, 3) 644 pregnancies in 144 patients with AD +MTHFR polymorphisms. PLs were classified into subgroups: a) Chemical Pregnancy(CP), b) Blighted Ovum(BO), c) gw ⩽ 10, d) gw11-14 e) gw15-22, f) Ectopic Pregnancy(EP), g) Trophoblastic Disease(TD). Obstetric histories were compared using Beksac Obstetrics Index (BOI): [number of living child + (π/10)]/gravida.

Results: PL rates before gw22 were 39.2% (58/148), 33.2% (105/316), and 36.3% (234/644) in AD, MTHFR, and AD +MTHFR groups, respectively (p= 0.421). The rate of Pre-Prenatal Screening Period fetal losses (CP + BO + gw ⩽ 10 fetal losses + EP + TD) were 84.8%, 75.9%, and 77.8% in AD, MTHFR, and AD +MTHFR, respectively (p= 0.264). Gravidity ⩽ 4 versus those with gravidity ⩾ 5 had statistically significant differences in BOI (p< 0.001).

Conclusions: PL rate before gw22 among singleton pregnancies with AD and/or MTHFR polymorphisms was 35.8%. The clinical findings seem to be more complicated in patients with gravidity ⩾ 5.

Keywords: Autoimmune disorders; blighted ovum; chemical pregnancy; methylenetetrahydrofolate reductase polymorphisms; miscarriage; pregnancy loss.