Early pregnancy concentrations of pregnancy-associated plasma protein-A (PAPP-A) and insulin-like growth factor-1 (IGF-1) following frozen embryo transfer: secondary analyses from a randomized controlled trial

What Was Tested

This randomized controlled trial paper looks at IGF-1 LR3.

Are maternal concentrations of pregnancy-associated plasma protein-A (PAPP-A) and insulin-like growth factor-1 (IGF-1) influenced by the frozen embryo transfer (FET) protocol in early pregnancy?

These markers may therefore provide insight into the pathways underlying the distinct risk profile of PC-FET.

Who Took Part

By PubMed's age tags, the people studied were adults, women only.

This is a secondary analysis from a randomized controlled trial investigating estradiol and progesterone concentrations in FET treatments.

The main analyses included women with ongoing pregnancies (n = 116), while additional analyses of IGF-1 were conducted in all ovulatory women with available biobank samples (n = 193).

How the Study Was Run

In design terms this was a randomized study.

Random assignment meant chance, not the researchers, decided who got IGF-1 LR3 and who got the comparison, which limits bias.

The trial was conducted at Copenhagen University Hospital-Herlev, Denmark, from April 2021 to December 2024.

Biochemical analyses for PAPP-A and IGF-1 were performed on stored biobank samples from the trial.

Eligible participants were women aged 18-40 years with BMI ≤35 kg/m2 undergoing frozen-thawed autologous blastocyst transfer.

Ovulatory women were randomized to mNC or PC, and anovulatory women to gSC or PC.

Samples were collected at the following 7 timepoints throughout treatment: on the 2nd or 3rd day of menstrual bleeding, on the day of trigger/endometrial thickness ≥7 mm, on the day of embryo transfer and by gestational ages (GA) 4 + 2, 6 + 0, 8 + 0, and 9 + 6.

What Was Measured

As this was a secondary analysis, no formal power calculation was made, and statistical power may therefore be limited.

The subject headings attached to it are Pregnancy-Associated Plasma Protein-A, Insulin-Like Growth Factor I, Embryo Transfer, Cryopreservation and Biomarkers.

Author keywords: early pregnancy, frozen embryo transfer, insulin-like growth factor 1, placenta and preeclampsia.

What This Means in Plain Language

The paper is a randomized study of IGF-1 LR3.

Results are reported in around 7 sentences of the abstract; we leave them to the paper itself rather than summarise them.

The publication is from 2026 (Human reproduction (Oxford, England)), a journal based in England.

More context: the IGF-1 LR3 compound page, all human trials.