Women with ADHD may be more likely to have some adverse outcomes during pregnancy, new research suggests – but medication may not be the cause
A study led by researchers from the University of Sydney and published in CNS Drugs aimed to determine whether ADHD, its treatment with stimulant medication, or both might adversely affect pregnancy outcomes.
The study of more than 5000 NSW women and their newborns is the largest of its kind to assess the impact of ADHD and commonly prescribed stimulant medications (dexamphetamine or methylphenidate) on mothers and their babies born between 1994 and 2012.
“Small increases of up to 20-30% were observed for a variety of adverse perinatal outcomes, including caesarean delivery, neonatal resuscitation and neonatal admission (all treatment categories); and pre-eclampsia, preterm birth and low 1-min Apgar score (treatment before or before and during pregnancy),” the authors write.
The researchers had compared these outcomes with a control group of babies and pregnancy outcomes of women who did not have ADHD and who were not treated with medications for ADHD.
But “the higher rates of adverse outcomes observed even in women yet to be treated or women who ceased stimulant medication several years prior to the pregnancy suggest that the increased risk is not predominantly, if at all, a direct effect of medication,” they write.
The rate of stimulant prescribing was only 3.5% during pregnancy, and dropped considerably during pregnancy.
“Based on the evidence of this study, the potential benefit of ceasing treatment for ADHD during pregnancy may be limited,” said lead author Alison Poulton, a paediatrician and senior lecturer at the University of Sydney.
The study linked and analysed data from two datasets: the NSW Pharmaceutical Drugs of Addiction System and the NSW Perinatal Data Collection (PDC).
Linkage of the two datasets identified a cohort of 5,056 women treated with stimulants for ADHD from 1982-2012 who gave birth between 1994 and 2012. An untreated cohort of women who did not have NSW prescription records for stimulant medication were recruited by selecting at random from the PDC five women matching each treated woman by maternal age and infant year of birth.
Of 5,056 women treated for ADHD with stimulant medication, 3351 (66.3%) had stimulant treatment documented before the index pregnancy but not within 1 year before the expected date of delivery, 175 (3.5%) had stimulant treatment before and possibly during pregnancy, and 1,530 (30.2%) had no stimulant treatment until after the index pregnancy.
Women in each treatment category were separately compared with all untreated women and odds ratios calculated for the perinatal outcomes using unconditional multiple logistic regression while adjusting for matching variables (baby’s year of birth and mother’s age) and the potential confounding effects of maternal age, parity, multiple pregnancy, cigarette smoking, pre-existing diabetes and hypertension.
Women treated for ADHD had statistically significantly higher rates of pre-existing diabetes and smoking in pregnancy regardless of when they were treated, for example.
ADHD or its treatment appeared not to be associated with gestational diabetes, instrumental vaginal delivery, post-partum haemorrhage requiring blood transfusion, birth weight of less than 2500g or over 4000g, or five-minute Apgar less than seven or perinatal death.
Women whose treatment preceded pregnancy had a higher risk for some additional adverse outcomes, including pre-eclampsia, pre-term birth earlier than 37 weeks and birth of a baby with a one-minute Apgar score of less than seven.
Part or all of the observed increases in perinatal risk could be due to ADHD itself, or factors associated with it other than stimulant therapy, the authors wrote.
“Research is needed to investigate directly the risks, both medical and social, of ceasing versus continuing stimulant treatment for ADHD during pregnancy.”
Women already taking medication for ADHD should not stop treatment without first consulting their doctor, they say.