Do you know how long your luteal phase lasts? The luteal phase is the second part of your menstrual cycle. It begins on the day of ovulation (or the day after a positive OPK) and ends with either the start of your next period or the beginning of a pregnancy.
This phase is incredibly important because it’s when your body produces progesterone, the hormone that stabilizes and thickens your uterine lining. If your luteal phase is less than 11 days, it may be harder to get pregnant or to stay pregnant due to lower progesterone levels and a uterine lining that isn’t fully prepared for implantation. This is known as luteal phase deficiency or luteal phase defect (LPD).
So what can help? Here are some research-backed, fertility-supportive strategies shown to improve luteal phase function and progesterone levels:
Vitamin C Supplementation
Studies have shown that vitamin C supplementation can improve hormone levels and fertility in women with luteal phase defects. In one study published in Fertility and Sterility, women who took 750 mg/day of vitamin C for three weeks saw significant improvements in progesterone levels. Over six months, 25% of these women conceived, compared to only 11% in the control group.
Healthy Vitamin D Levels
Vitamin D plays a crucial role in hormone regulation, and deficiency is widespread. Low vitamin D has been linked to reduced estrogen and progesterone levels, increasing the risk of a shortened luteal phase. Ensuring optimal levels (via sunlight, diet, or supplementation) may support healthier luteal function.
Adequate Folate Levels
Folate, the natural form of vitamin B9, is essential for hormone production and early pregnancy. Even mild folate insufficiency has been associated with reduced progesterone levels in the luteal phase. A high-quality prenatal with methylated folate can help correct this.
Progesterone Cream
For some women over 40, natural progesterone production may not be sufficient despite healthy lifestyle habits and nutrient support. In these cases, a cream or vaginal suppositories can be helpful to boost progesterone levels and support the uterine lining, improving the chances for implantation and early pregnancy. Natural progesterone cream is a common treatment for luteal phase deficiency. It’s typically applied daily after ovulation until menstruation and often continued into early pregnancy when conception occurs.
Understanding your luteal phase is just one piece of the fertility puzzle, and there is so much more you can do to naturally support progesterone, improve cycle health, and increase your chances of conceiving in your 40s.
If you want step-by-step guidance, science-backed strategies, and a clear plan for improving your fertility, my Fertile After 40 Masterclass is the perfect place to start. You’ll learn exactly how to optimize your hormones, support egg quality, strengthen your luteal phase, and prepare your body for a healthy pregnancy.
You don’t have to guess. You can take control — and I’ll show you how inside the Masterclass.
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PMID: 33827766, 34977455, 32068843, 31056309, 29762856, 28854586, 25681845