This is a prospective, multicenter, observational study designed to evaluate the effectiveness and safety of Bictegravir/Emtricitabine/Tenofovir Alafenamide (B/F/TAF) in pregnant women living with HIV. Given the limited prospective data on B/F/TAF use during early pregnancy, this study aims to address the evidence gap by observing women who are on B/F/TAF for at least six months with sustained viral suppression (HIV RNA <50 copies/mL) and are within the first trimester. Participants will continue B/F/TAF throughout pregnancy and up to 12 weeks postpartum per routine clinical practice. No experimental intervention will be assigned. The primary objective is to assess the proportion of participants achieving HIV RNA <50 copies/mL at 12 12 weeks of pregnancy. Secondary objectives include maternal viral suppression at 28 weeks, delivery, and postpartum; safety and tolerability; maternal and neonatal outcomes including congenital anomalies, APGAR scores, infant HIV status, and growth parameters. The study will enroll at least 50 participants across five clinical centers in China. Findings will provide real-world evidence on the use of B/F/TAF as an alternative integrase inhibitor-based regimen for pregnant women with HIV.

Statistical Methods Descriptive statistics will be used to summarize the data. Continuous variables will be presented as means with standard deviations and medians with interquartile ranges, depending on the distribution of the data. Categorical variables will be described by their frequency distribution and ranges (Two-sided 95% confidence).

Efficacy:

The proportion of participants with plasma HIV RNA <50 copies/mL at the time of delivery will be summarized using the missing = excluded approach for imputing missing HIV RNA values.

Safety:

The adverse events (AE) data will be listed by subject. Treatment-emergent AEs, Grade 1-4 AEs will be summarized by system organ class, and preferred term using the current version of the Medical Dictionary for Regulatory Activities (MedDRA), and graded according to the DIADS Table for Grading the Severity of Adult and Pediatric Adverse Events .

Listings of individual subject vital signs, 12-lead ECG parameters, and laboratory results will be provided. Laboratory abnormalities will be graded for severity using the DAIDS Table for Grading the Severity of Adult and Pediatric Adverse Events. Laboratory results and changes from baseline for vital signs and selected lab tests will be summarized at scheduled visits. The incidence and grade of treatment-emergent laboratory abnormalities will be summarized accordingly.

Maternal/neonatal outcomes analysis Proportion of infants with confirmed negative or positive HIV RNA testing will be summarized using the missing = excluded approach for imputing missing HIV RNA values.

Proportion of live births, stillbirths, and pregnancy loss will be summarized. APGAR scores will be summarized. Adverse events and toxicity management

Definitions of Adverse Events, Adverse Reactions, and Serious Adverse Events:

Adverse Events An AE is any untoward medical occurrence in a clinical study subject administered a pharmaceutical product, which does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and/or unintended sign, symptom, or disease temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. AEs may also include lack of efficacy, overdose, drug abuse/misuse reports, or occupational exposure.

Inclusion Criteria:

1. Women with aged 18 years or older and confirmed HIV infection.
2. Currently on B/F/TAF for 6 months preceding the screening visit.
3. Documented plasma HIV RNA<50 copies/mL for 6 months preceding the screening visit and have HIV RNA<50 copies/mL at the screening visit.
4. Women within 12 weeks of pregnancy at the time of screening.
5. The ability to understand and sign a written informed consent form, which must be obtained prior to initiation of study procedures.

Exclusion Criteria:

1. Have active hepatitis C virus (HCV) infection.
2. An opportunistic illness indicative of stage 3 HIV diagnosed within the 30 days prior to screening.
3. Other clinical scenarios that are no longer suitable for B/F/TAF therapy (Such as electrocardiogram, liver and kidney dysfunction, opportunistic infection and so on).

Pregnant women with HIV who receiving B/F/TAF for at least 6 months, virus suppressed (VS) for more than 6 months and who are in first trimester.