Pregnant women with heart disease should give birth at no later than 40 weeks gestation. That is one of the recommendations in the 2018 European Society of Cardiology (ESC) Guidelines for the management of cardiovascular diseases during pregnancy published online today in European Heart Journal, and on the ESC website.

"Beyond 40 weeks, pregnancy has no added benefit for the baby and may even have negative effects," said Professor Jolien Roos-Hesselink, Co-Chairperson of the Guidelines Task Force and Cardiologist, Erasmus Medical Centre Rotterdam, the Netherlands. "Pregnancy is a risky period for women with heart disease because it puts additional stress on the heart, so the guidelines advise inducing labour or a caesarean section at 40 weeks."

Heart disease is the main reason women die during pregnancy in western countries. Compared to healthy pregnant women, those with heart disease have a 100-fold greater risk of death or heart failure. Most women with heart disease have a healthy pregnancy. However, they should be aware that they have a higher risk of obstetric complications including premature labour, pre-eclampsia, and post-partum bleeding. An estimated 18-30% of offspring have complications and up to 4% of neonates die.

Heart disease in pregnancy is increasing as more women with congenital heart disease reach adulthood due to improved treatment and as the age at first pregnancy rises, accompanied by the higher rates of ischaemic heart disease in older, compared to younger, women. Cardiovascular risk factors including hypertension, diabetes and overweight are also on the rise in pregnancy as older women become pregnant and women now acquire risk factors at a younger age.

The guidelines provide recommendations on in vitro fertilisation (IVF), contraception, and termination of pregnancy in women with heart disease. IVF often uses high doses of hormones, which increase the risk of thrombosis and heart failure, so women with heart disease need a cardiologist's confirmation that the chosen method is safe. Since carrying more than one baby puts more stress on the heart, women with heart disease undergoing IVF are strongly advised to transfer a single embryo. Girls with congenital heart disease need contraception advice to avoid unplanned pregnancy. Some contraception methods are contraindicated in patients with certain types of heart disease.

For drugs used to treat heart disease, the guidelines list information on adverse events obtained from human and animal studies. In addition, the guidelines state: "In the case of an emergency, drugs that are not recommended by the pharmaceutical industry during pregnancy and breastfeeding should not be withheld from the mother. The potential risk of a drug and the possible benefit of the therapy must be weighed against each other."

Professor Vera Regitz-Zagrosek, Chairperson of the Guidelines Task Force and Director of the Institute for Gender Medicine, Charité University Medical Centre Berlin, Germany, said: "When drug companies have no data on whether a drug is safe during pregnancy and breastfeeding they tend to say it is not recommended. It may be appropriate to give a drug to a severely ill woman if there are no harmful side effects noted in the databases listed in the guidelines."

Pregnancy is not recommended in patients with certain types of heart disease -- for example, pulmonary arterial hypertension, severely dilated aorta, or severely reduced ability of the heart to pump blood.

Women with heart disease who want to have a baby need pre-pregnancy risk assessment and counselling. Those at moderate to high risk of complications should be reviewed by a pregnancy heart team with a cardiologist, obstetrician, gynaecologist, and anaesthesiologist. A delivery plan should be devised at 20-30 weeks specifying vaginal or caesarean delivery, whether an epidural or forceps will be used, and the duration of hospital stay after delivery.

Professor Roos-Hesselink said: "The delivery plan should be available 24 hours a day so that when a pregnant woman with heart disease arrives at hospital in labour hospital staff know exactly what to do."

Professor Regitz-Zagrosek: "We hope the guidelines will improve doctors' awareness of the risks of heart disease in pregnancy but also the therapeutic options that are available to guide pregnancy in these women."