Women with congenital heart disease need to be cautious about pregnancy and birth control choices because some options can increase heart risks, but many are unaware of the concerns, a new study suggests.

The research involving 536 German women born with heart defects found that nearly half had not been counseled about their risks related to contraception and pregnancy. What’s more, of the women with contraindications to using birth control pills, 20 percent were currently taking them.

The findings point to a need for greater awareness among both women and their doctors of the risks certain contraceptives present for women whose hearts are already compromised, researchers report in the American Journal of Cardiology.

Many women with heart conditions can safely become pregnant or use contraceptives to prevent pregnancy. But certain severe congenital heart conditions raise the risks both of pregnancy complications and adverse effects from various birth control options.

In the German study group, roughly one third of the women had contraindications to using birth control pills containing estrogen and progesterone, which can cause blood clots and raise blood pressure in some users.

That included women with conditions considered “absolute” contraindications to using the Pill, such as severe heart failure; cyanotic heart defects, which limit the circulation of oxygen throughout the body; a history of blood clots; and a rare heart defect called Eisenmenger’s syndrome that is marked by high blood pressure in the lungs (known as pulmonary hypertension).

The group also included women with “relative” contraindications to oral contraceptive use, including smoking and arterial high blood pressure.

Of these at-risk women, 34 - or nearly 20 percent - were nonetheless currently using the Pill.

In addition, 43 percent of the women overall said they had never been counseled about birth control.

An even larger proportion of the group was unaware that pregnancy would also present special risks for them - 48 percent said their doctors had never talked with them about pregnancy or any pregnancy-related risks associated with their condition.

During pregnancy, a woman’s blood volume and heart rate increase, putting an increased strain on the organ. Women with certain heart conditions - including severe heart failure, cyanotic heart defects and Eisenmenger’s - are considered to be at high risk of complications.

Sixty women in the current study fell into this high-risk group, 39 of whom were of reproductive age and sexually active. Of these, 28 percent were not using any birth control at all.

It is not surprising that so many women in the study lacked any counseling on pregnancy and contraception, according to senior researcher Dr. Harald Kaemmerer, of the German Heart Center Munich.

The area of “adult congenital heart disease” - that is, caring for adults who have survived inborn heart defects - is new even within the field of cardiology, he told Reuters Health in an e-mail. Many doctors, including gynecologists, may not be aware of the specific pregnancy-related issues related to the various types of congenital heart defects, Kaemmerer explained.

Besides birth control pills, certain other contraceptives may carry risks for some women. It is not clear, for example, whether intrauterine devices (IUDs) might pose a risk of endocarditis - an infection of the lining of the heart - in vulnerable women, such as those who have had a heart transplant.

Options such as condoms and diaphragms would bypass the risk of drug-related side effects, but they tend to have high failure rates among teenagers and women who are not in stable relationships, Kaemmerer and his colleagues note.

According to Kaemmerer, decisions on birth control need to be made on an individual basis, based on a woman’s particular heart problem.

He advised women to bring up these questions with their cardiologist if they have not yet been addressed.

He and his colleagues also call for a “stronger collaboration between cardiologic and family planning experts” to increase awareness of these issues among doctors, and by extension women with congenital heart disease.

The findings are based on 536 young women who were seen over one year at the outpatient clinic of two German medical centers specializing in treating adults with heart disease. The women completed questionnaires on their sexual history, contraceptive use and any discussions they’d had with their doctors on pregnancy and birth control.

Since medical practices vary from country to country, it is not clear whether similar findings would be seen outside Germany, Kaemmerer said.

He and his colleagues are now conducting similar studies in parts of Eastern Europe and in Japan to find out.

SOURCE:  American Journal of Cardiology, online September 14, 2010.