Probability and outcomes of second pregnancy after HELLP syndrome in the first: A population-based registry study

Some studies have suggested that women may avoid further pregnancies after experiencing a pregnancy affected by a hypertensive disorder. Large population-based studies are needed to better understand the outcomes of later pregnancies among women who have a history of hypertensive disorders of pregnancy. The aims of the study were to assess outcomes of the second pregnancy and second delivery rate among women experiencing Hemolysis, elevated liver enzymes and low platelet count (HELLP) syndrome in their first pregnancy.

This population-based registry study included all women with a first delivery registered in the Medical Birth Registry of Norway from 1999 to 2014 (n = 418 897). Logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for adverse outcomes of the second delivery and the probability of no second delivery among women with HELLP syndrome in first pregnancy compared with women without HELLP syndrome. We also compared outcomes in the first and second pregnancies among women with HELLP syndrome in first.

HELLP syndrome occurred in 0.24% of first pregnancies (n = 1006). Among women with HELLP syndrome in their first pregnancy, adverse outcomes were substantially less frequent in the second pregnancy: preterm deliveries declined from 56.0% to 14.2%, and small for gestational age from 6.6% to 2.8%. More than 75% had no hypertensive disorder in their second pregnancy. Still, compared with women without a history of HELLP syndrome, ORs for adverse outcomes in second pregnancies were increased: preterm birth (OR 3.7, 95% CI 2.8-4.8), small for gestational age (OR 2.7, 95% CI 1.6-4.8), perinatal death (OR 3.1, 95% CI 1.4-7.0), placental abruption (OR 4.2, 95% CI 1.8-9.4) and hypertensive complication (OR 8.3, 95% CI 6.7-10.3). HELLP syndrome did not influence the probability of a second delivery.

Among women with HELLP syndrome in their first pregnancy, the occurrence of adverse pregnancy outcomes was substantially reduced in the second pregnancy. However, compared with unaffected women, they were still at greater risk of pregnancy complications.