The rate of recurrent GDM is high. It is uncertain as to whether outcomes are better or worse in the subsequent pregnancy. This study compared maternal and neonatal outcomes in consecutive GDM pregnancy pairs.
This was a retrospective study of 424 consecutive GDM pregnancy pairs from two Sydney centres. Women with >1 GDM pregnancy were identified through in-house GDM databases. Demographic data were also obtained from the Obstetrix database and medical records.
Women were 2.9±1.6 years older in the second GDM pregnancy, with a mean weight increment of 2.6±6.0kg and BMI increment of 0.9±2.6kg/m2 (p<0.001 for both). GDM was diagnosed 4.6±6.9 weeks earlier and medication commenced 4.5±7.3 weeks earlier (p<0.001 for both). GDM was diagnosed prior to 22 weeks in 44% of second pregnancies versus 10% of first pregnancies (p<0.001), with a greater proportion requiring medication.
Second GDM pregnancies were less likely to require ventouse/forceps (5% vs 14%, p<0.001) or emergency caesarean section (7% vs 16%, p<0.001), perhaps related to increased caesarean and elective sections in this group (p<0.001). There was no difference in customised birth weight centiles or neonatal complications such as shoulder dystocia, hypoglycemia, SGA/LGA, foetal/neonatal death, or a combination of these outcomes.
Having an adverse outcome was highly predictive of a similar outcome in the subsequent pregnancy. There was a 33% risk of SGA in the second pregnancy and 45% risk of LGA in with women with previous SGA or LGA. Having a ventouse/forceps delivery, emergency section or perinatal death/dystocia/LGA/SGA outcome in the first pregnancy was associated with a 3.1-, 2.2- and 2.1-fold risk of the same outcome in the 2nd pregnancy compared to women without these complications.
Our findings emphasize the importance of early screening/intervention in women with a history of GDM, targeting the most intensive treatment to those with adverse outcomes the first time around.