Women living with HIV face multiple challenges regarding pregnancy, encompassing not only their intention to procreate, but also difficulties during the course of pregnancy.

Compared to HIV-negative controls, HIV-infected women have a higher risk of pregnancy complications such as preeclampsia, gestational diabetes, or preterm labor. In addition, the treatment of HIV among pregnant women entails specific difficulties, such as changes in bioavailability of antiretroviral drugs, or the concern about the association of certain antiretrovirals with adverse pregnancy outcomes.

There is very little evidence about pregnancy among women living with HIV in Spain. Very few studies have been published, performed in single centers or in small cohorts with a limited number of patients. The Cohort of the Spanish AIDS Research Network (CoRIS) offers a unique setting to answer questions that are unlikely to be answered by a single study.

The aims of this study are (i) to describe the incidence of pregnancies and their temporal trends from 2004 to 2019, (ii) o describe the clinical and epidemiological characteristics of women who become pregnant, (iii) to assess the diagnostic delay among women diagnosed with HIV infection after becoming pregnant, (iv) to investigate the clinical course during pregnancy and its predictive factors, (v) to describe the antiretroviral treatment administered to pregnant women, (vi) to describe clinical outcomes after pregnancy, (vii) to describe the outcome of the conception in terms of interrupted pregnancies, spontaneous abortions, term pregnancies, type of delivery (vaginal or caesarean section) and HIV infection of the newborn, and (vii) to evaluate attitudes towards pregnancy (ie. planned pregnancy) and social support among women who become pregnant during the year 2020.

Study population will be women from the cohort of the Spanish AIDS Research Network (CoRIS) who have become pregnant in the period 2004-2010.

Inclusion Criteria:

• HIV-positive women recruited in CoRIS
• Became pregnant from January 2004 to November 2019
• or become pregnant during the year 2020 and agree to participate in a telephone survey

The Cohort of the Spanish AIDS Research Network (CoRIS) is a prospective multicentre cohort of HIV-positive treatment-naïve patients aged >13 years, recruited from 46 centres from 13 Autonomous Regions in the Spanish public healthcare system. Recruitment and follow-up started in 2004 and are still ongoing. From 2004 to the last update in November 2018, 15,509 patients have been included in the cohort. This study will be performed using the update of November 2019, that will be available in June 2020.

Data cannot be made publicly available because they are owned by a third party, the AIDs Research Network (RIS), and because participants agreed that data would only be used for research projects by RIS or those projects approved by its

Executive and Scientific Committee. Interested readers may send requests for the data to proyectoscoris@gmail.com. Requests will be assessed by the Executive and Scientific Committee