A new report suggests that natural conception may be a safe option for heterosexual couples in which one partner is HIV positive and the other is HIV negative. The conclusions of the Spanish study reported in the November 1 issue of the Journal of Acquired Immune Deficiency Syndromes suggest that unprotected vaginal intercourse to achieve pregnancy, provided that the HIV-positive partner is on HIV drug treatment and has an undetectable viral load, may be associated with a minimal risk of HIV transmission.

For people living with HIV today, pregnancy is no longer the medically and ethically challenging situation it once was. For starters, antiretroviral treatment can potentially extend an HIV-positive person’s life by decades, making 18-plus years of child rearing a possibility. Second, HIV-positive mothers-to-be can drastically reduce their risk of transmitting the virus to their babies – to less than 2% – with proper use of HIV treatment during pregnancy.

A lingering challenge faced by many couples affected by HIV – especially those in which one partner is HIV positive and the other is HIV negative – wanting to become pregnant is the best way to go about conceiving. Given that natural conception – unprotected vaginal intercourse – may put the HIV-negative partner at risk for infection through exposure to his or her HIV-positive partner’s genital fluids, many mixed-status couples have turned to artificial means for assistance. For example, there’s “sperm washing” and in vitro fertilization, two expensive and time consuming options. There are also crude and highly unreliable at-home protocols calling for artificial insemination with the use of turkey basters and other utensils.

Previous studies have documented that HIV-positive people with “maximally suppressed” virus while on HIV drug treatment are significantly less likely to pass their virus along to their sexual partners. In turn, a team of Spanish researchers took a look at the transmission risk associated with natural conception among mixed-status couples, in which the HIV-positive partner had an undetectable viral load as a result of antiretroviral therapy.

The study reviewed the files of 62 mixed-status couples who opted to conceive naturally between 1998 and 2005. The HIV-positive partner was the man in 40 (65%) cases and the woman in 22 (35%) cases. The average viral load, at the time of conception, was less than 500 in both the male and female infected partners. All HIV-positive mothers had undetectable viral loads at the time of delivery.

A total of 76 pregnancies among the 62 couples were documented during the seven-year period. Fifty-two couples had only one pregnancy during this time, six couples reported two pregnancies, and four couples had three pregnancies. There was one case of twin pregnancies and nine miscarriages (which were more common among the HIV-positive women than the HIV-negative women).

The authors reported that, in all cases, the HIV-negative partner remained uninfected.

There was, however, one case of mother-to-child transmission. Even though HIV treatment was used to reduce the risk of infection, a baby born to a 37-year-old HIV-positive woman was diagnosed with AIDS-related Pneumocystis pneumonia (PCP) during the third week of life and subsequently died.

Aside from their conclusion that mixed-status couples “attaining natural pregnancy are exposed to a negligible risk of sexual transmission of HIV when the infected partner [has an undetectable viral load] while on [HIV drug treatment],” the researchers also provided some useful conception recommendations.

“If the couple has opted for natural pregnancy,” they write, “undetectable viremia is mandatory and pregnancy is discouraged in patients with any levels of HIV replication.” They add that other transmissible infections (e.g., viral hepatitis), cofactors that can increase the risk of transmission (e.g., inflammation, infection, or dysplasia of the genital tract), and fertility potential should all be evaluated carefully before attempting natural conception. Finally, “it is important to advise these couples to restrict overt sexual contacts to fertile days exclusively, for which the use of ovulation tests may be recommended. Pregnancy attempts should be limited in number, and couples should receive medical reassessment if conception does not occur in three to six months.”