Blood fats were linked to fewer eggs in IVF, but age and AMH mattered more

Higher triglycerides were linked to fewer eggs retrieved in 8,851 women with low ovarian reserve doing IVF, but didn’t independently predict pregnancy or live birth, in a study combining genetic data and clinical records published Sept. 15, 2026, in Frontiers in Endocrinology. For fertility, age and AMH remained the dominant factors.

Ovarian reserve, the supply of eggs a woman has left, falls with age and faster in some women. Low reserve makes fertility treatment harder. Researchers have wondered whether metabolism, including blood fats, plays a role.

What did the study look at?

The team used two approaches. First, Mendelian randomization, a method that uses natural genetic differences as a kind of natural experiment to test whether a factor may cause an effect. Second, records of 8,851 women with diminished ovarian reserve going through their first IVF or ICSI cycle, to see how triglycerides related to hormones and the number of eggs retrieved.

What did the study find about fertility?

• Genetically higher triglycerides were linked to lower FSH, a hormone that rises when ovarian reserve falls.
• Triglycerides showed no causal effect on AMH, the main marker of ovarian reserve.
• In the clinical data, higher triglycerides had a direct negative effect on the number of eggs retrieved, partly offset by the lower FSH (suppression proportion 23.6%).
• Triglycerides did not independently predict clinical pregnancy or live birth; age and AMH remained the dominant factors.

Why does this matter?

Triglycerides can be lowered with diet, exercise, less alcohol and, if needed, medicine. If they affect how many eggs are retrieved, they could be a modifiable factor for women preparing for IVF. But the study shows their effect is complex and that age remains the main driver of results.

How solid is this evidence?

It’s moderate. Mongevity rates it C on our A-to-E scale: genetic analyses plus a large retrospective cohort. Limits: Mendelian randomization relies on assumptions that can’t be fully checked, the clinical data were retrospective and from a specific population, and the effects found were small.

What are the open questions?

Trials would be needed to see whether lowering triglycerides before IVF actually increases egg yield or births in women with low ovarian reserve.

What does this mean for you?

If you’re planning fertility treatment, a healthy metabolism helps your general health and may help the process: balanced meals with fewer refined carbs and sugary drinks, regular movement and limited alcohol. But age remains the biggest factor, so don’t delay seeking advice if you’re concerned.

How do I explain this at dinner?

Scientists asked whether fats in the blood affect women’s egg supply. Higher levels were linked to fewer eggs in IVF, but they didn’t change the chance of a baby, which depended mostly on age. A good question for the table: what part of fertility can we influence and what part can’t we?

In one sentence: in women with diminished ovarian reserve, triglycerides were linked to lower FSH and fewer retrieved eggs, but did not independently predict pregnancy or live birth.