Extreme βHCG levels in first trimester screening are risk factors for adverse maternal and fetal outcomes

Multiples of the normal median (MoM) of free βHCG is a valuable parameter in evaluation of risk of adverse pregnancy outcomes. In the current retrospective study, we assessed the maternal and fetal outcomes in pregnant women having free βHCG MoM levels < 0.2 or > 5 in their first trimester screening (FTS). Relative risk of trisomy 21 was significantly higher in patients having free βHCG MoM > 5. On the other hand, relative risk of trisomies 13 and 18 and Turner syndrome were higher in those having free βHCG MoM < 0.2. Other chromosomal abnormalities were nearly equally detected between those having free βHCG MoM < 0.2 or > 5. Relative risk of hydrocephaly and hydrops fetalis was higher when free βHCG MoM was below 0.2. On the other hand, relative risk of low birth weight was higher when free βHCG MoM was above 5. Moreover, frequency of gestational diabetes mellitus, preeclampsia, preterm delivery and vaginal bleeding increased with levels of free βHCG MoM. However, polyhydramnios had the opposite trend. Frequencies of premature rupture of membranes and pregnancy induced hypertension were highest among pregnant women having levels of free βHCG MoM < 0.2. The current study indicates importance of free βHCG MoM in identification of at-risk pregnancies in terms of both fetal and maternal outcomes. In fact, βHCG MoM < 0.2 or > 5 can be regarded as risk factors for adverse maternal or fetal outcomes irrespective of the presence of other abnormalities in the FTS results.