Maternal haemoglobin drop in multiple pregnancy is associated with
increased gestational age at delivery and birthweight: A retrospective
study
Abstract
Objective: To investigate the hypothesis that maternal
haemoglobin (Hb) levels in twin pregnancy fall between the first and
second trimesters, and that the size of the fall is associated with
gestational age at birth and birthweight (BW). Design:
Retrospective study. Setting: Inner London Maternity Unit.
Population: Pregnant women with twin pregnancies delivering two
live, phenotypically normal neonates, after 24 +0
weeks of gestation, between October 2009 and September 2021.
Methods: Measurement of Hb, at ≤14 +0 weeks
of gestation, (Hb1) and again at 20 +0-30
+0 weeks gestation (Hb2). Hb drop was defined as
Hb1-Hb2. Small for gestational age was defined as BW <10th
percentile for gestation. The association of Hb drop with gestational
age at birth, BW, SGA and intertwin BW discrepancy of ˃25%, was
evaluated. Main outcome Measures: Gestational age at birth
, incidence of SGA neonates and/or intertwin BW discrepancy
>25%. Results: 925 women with twin pregnancies.
Maternal Hb1 did not correlate with gestational age or SGA or twins with
BW discrepancy >25%. However, a larger Hb drop was
associated with a higher gestational age at birth (p<0.001), a
larger BW of both twin 1 and 2 (p<0.001) and a trend towards
reduction in the incidence of delivering one or two SGA neonates
(p=0.005 and p=0.003, respectively) or twins with BW discrepancy of
>25% (p=0.005). Conclusions: The study has shown
that a larger maternal Hb drop from the first to the second trimester is
associated with a higher gestational age at birth, a larger BW and
smaller BW discrepancy in twin pregnancies.