Increased time-to-pregnancy and first trimester Down's syndrome screening

Area of Science:

• Reproductive Medicine and Endocrinology
• Prenatal Diagnostics and Screening

Background:

• Time-to-pregnancy (TTP) is a key indicator of female fertility and uterine receptivity.
• Understanding TTP's impact on early pregnancy markers is crucial for accurate Down's syndrome (DS) screening.
• This study investigates TTP's effect on DS screening markers in spontaneous versus IVF pregnancies.

Purpose of the Study:

• To evaluate the influence of TTP on first-trimester Down's syndrome (DS) screening markers.
• To compare these effects in spontaneous pregnancies with varying TTPs and in vitro fertilization (IVF) pregnancies.
• To explore potential links between prolonged TTP, subfertility, and altered screening profiles.

Main Methods:

• A case-control study analyzed data from 1385 singleton pregnancies in Finland (2005-2007).
• First-trimester DS screening data included maternal age, serum free beta-hCG (fbeta-hCG), PAPP-A, and nuchal translucency (NT).
• Spontaneous pregnancies were grouped by TTP (0-12, 13-24, >25 months); IVF pregnancies served as a comparison group.

Main Results:

• Significantly lower PAPP-A levels were observed in pregnancies with TTP >25 months and in the IVF group compared to the reference group (TTP 0-12 months).
• No significant differences in fbeta-hCG or NT multiples of median (MOM) were found between groups.
• The rate of DS screening positives was markedly higher in women with TTP >25 months (12.9%) versus the reference group (2.1%).

Conclusions:

• A TTP exceeding 2 years is associated with altered DS screening markers, specifically decreased PAPP-A, similar to IVF pregnancies.
• These marker changes suggest a potential link to underlying subfertility rather than assisted reproductive technology itself.
• Prolonged TTP may warrant further investigation in the context of prenatal screening and reproductive health assessments.