When preparing for pregnancy, are you always focused on AMH and follicles? This often overlooked “endocrine organ” may also be affecting reproductive health.

Always focused on AMH and follicles when preparing for pregnancy? This often-overlooked “endocrine organ” may also be affecting reproductive status

During preconception checkups, most people focus on similar markers: the six-item sex hormone panel, AMH, thyroid function, antral follicle count on ultrasound, and endometrial thickness. Especially for women who have already entered an IVF cycle or are preparing to travel to Thailand for Thai third-generation IVF, how high AMH is, how many basal follicles there are, and how many eggs can be retrieved after ovarian stimulation have become the numbers most likely to cause anxiety in each cycle.

These markers are of course important, but they mostly help us observe ovarian function and the state already presented by the reproductive system. Behind the metabolic environment, energy utilization, and endocrine regulation in which follicles develop, there is another tissue often regarded as merely a “motor organ”—skeletal muscle. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception…

In the past, when we mentioned muscle, we first thought of strength, exercise, and body shape management. But endocrine research in recent years has continued to expand our understanding of skeletal muscle: skeletal muscle not only performs motor functions but is also an important endocrine tissue that can produce a variety of biologically active “myokines.”

This means that for people preparing for pregnancy, undergoing repeated assisted reproductive treatment, or planning overseas fertility care or cross-border childbirth, in addition to focusing on the ovaries and uterus, the body’s metabolic and muscle status is also a dimension worth understanding.

I. Skeletal muscle is not only responsible for movement; it also participates in endocrine regulation

The human endocrine system is not several isolated organs working separately, but a complex interconnected network. During exercise, skeletal muscle can release a variety of myokines that communicate with other tissues through the bloodstream, and the reproductive system has therefore become one of the areas of research attention in recent years.

A 2025 mouse model study published in Science found that myostatin produced by skeletal muscle can promote the pituitary gland’s synthesis of follicle-stimulating hormone (FSH), suggesting a previously underrecognized “skeletal muscle–pituitary–ovary” endocrine regulatory pathway. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception…

FSH is familiar to people undergoing IVF. It participates in follicular recruitment and development and is one of the very important hormones in ovarian stimulation treatment. However, the current significance of this study lies more in helping us further understand the reproductive endocrine network, rather than simply concluding that “the more muscle, the higher FSH, the better the eggs.”

Another myokine receiving attention is irisin. Studies have found that irisin can be detected in follicular fluid, and granulosa cells also express its precursor protein FNDC5. Some studies suggest that it may be involved in mitochondrial biogenesis and oxidative phosphorylation and may be related to the process by which oocytes respond to oxidative stress. However, some evidence in this field still comes from animal models, so how much impact it can have on human reproductive outcomes requires confirmation from more high-quality research. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception…

Therefore, a more accurate understanding is not that “building muscle can directly improve egg quality,” but rather: skeletal muscle may participate in the regulation of the reproductive system through myokines, energy metabolism, and the endocrine network; it is not an organ entirely unrelated to the ovaries.

II. Is there really a relationship between muscle mass and IVF outcomes?

In addition to basic research, some clinical observations have also begun to focus attention on the relationship between muscle mass and female reproductive outcomes.

A 2024 case-control study found that, in its study sample, women with infertility had lower muscle mass than women with normal fertility. Another retrospective study of 990 patients undergoing IVF found that a higher percentage of appendicular skeletal muscle mass was statistically associated with a greater number of oocytes retrieved, number of usable embryos, number of blastocysts, and a higher cumulative clinical pregnancy rate; the mediation analysis in the study also suggested that insulin resistance may explain part of this association. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception…

But there is a very important distinction here: “there is an association” does not equal “a causal relationship has been proven.”

We cannot conclude from this that “gaining a few kilograms of muscle will definitely yield several more eggs” or that “starting strength training will improve IVF success rates.” Age, ovarian reserve, nutritional status, insulin sensitivity, exercise habits, and other health factors may all be involved at the same time.

What is truly worth noting is another issue: looking only at BMI may not fully reflect a person’s body composition.

Some women have completely normal weight and a BMI in the normal range, but a relatively high body fat percentage and relatively low muscle mass—what is commonly called “skinny fat.” Therefore, if you have been trying to conceive for a long time, have experienced repeated IVF failures, or have long relied on dieting during weight loss, rather than focusing only on the number on the scale, you can also discuss with your doctor whether it is necessary to learn more about your body fat percentage and muscle mass.

III. Which women preparing for pregnancy should pay more attention to the “muscle” dimension?

Not everyone preparing for pregnancy needs to treat muscle mass as a new source of anxiety. It is better suited as a supplementary dimension in an overall reproductive health assessment, rather than a new marker to replace AMH, AFC, age, or embryo quality.

People with normal weight but relatively high body fat, people who develop irregular menstruation after long-term dieting or a low-carbohydrate diet, women with polycystic ovary syndrome (PCOS), as well as those who are older, have decreased ovarian reserve, premature ovarian insufficiency, recurrent implantation failure, or have been on prolonged rest during IVF cycles. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception… The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception…

This is especially worth reminding women who are losing weight while preparing for pregnancy. Preparing for pregnancy is not about “the thinner, the better,” and it is even less true that the faster weight is lost, the better it is for conception. If rapid weight loss is achieved through long-term low-calorie dieting, extreme low-carbohydrate intake, or large amounts of aerobic exercise, although weight may decrease, a large amount of lean body mass may also be lost, and menstrual irregularities may even occur; this approach may not be beneficial to overall reproductive health.

Muscle and ovaries also share another common background—the hormonal environment. With changes in estrogen levels during perimenopause, ovarian function and skeletal muscle status may be affected at the same time; related research has also observed certain associations between circulating estradiol and progesterone levels and lean body mass. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception…

For women undergoing IVF or Thai third-generation IVF, this also reminds us that reproductive health does not involve only the “ovaries” as a single working organ. Age, ovarian reserve, metabolic status, nutrition, muscle, body fat, and the uterine environment are themselves interconnected.

IV. If you want to improve your physical condition, you can start with these 4 things

If in the past you have focused only on weight, AMH, and follicle count, you can try incorporating “body composition” into your preconception health management. However, the goal is not to build visibly large muscles, but to maintain a reasonable muscle mass and stable metabolic state as much as possible.

First, understand your body composition, not just your weight. If conditions allow, you can undergo a body composition analysis to get an approximate understanding of your body fat percentage, lean body mass, and muscle mass. Especially for people with a normal BMI but noticeable waist and abdominal fat, long-term lack of exercise, or a history of rapid weight loss, focusing only on weight often makes it easy to overlook changes in body composition.

Second, ensure basic nutrition and protein intake. A reference protein intake is about 1.2–1.5 grams per kilogram of body weight per day; for example, a 55 kg woman would require about 66–82 grams per day. It is also recommended to appropriately include foods such as beans, soy products, and nuts. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception… Specific intake does not need to be copied exactly by everyone; especially if you have kidney disease, special metabolic diseases, or other dietary restrictions, adjustments should be made according to the advice of a doctor or nutrition professional.

Third, if your physical condition allows, add regular resistance training. Squats, glute bridges, core training, and other basic strength movements can all be started at low intensity. It is recommended that people without exercise habits begin with bodyweight training, about 20–30 minutes each time; the cited exercise recommendation for PCOS is 150–300 minutes of moderate-intensity aerobic exercise per week, plus resistance training twice a week on non-consecutive days. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception…

Fourth, after entering an IVF cycle, do not simply copy a regular fitness plan. During ovarian stimulation, as the ovaries enlarge, exercise methods need to be adjusted according to your physical condition; activity before and after transfer should also follow the specific recommendations of your reproductive doctor. In particular, for 1–2 weeks after transfer, high-intensity exercise, heavy lifting, and movements that significantly increase abdominal pressure should be avoided, but this does not mean absolute bed rest is required; light activities such as walking can usually be done according to your doctor’s advice. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception…

For families planning to travel to Thailand for overseas fertility care, cross-border childbirth, or Thai third-generation IVF, in particular, do not increase training intensity on your own during ovarian stimulation, egg retrieval, or transfer simply because you have read that “exercise may be beneficial.” Ovarian size, hormone levels, and physical responses differ at each stage, and exercise plans should be adjusted according to the treatment stage.

Stop focusing only on AMH: what truly matters in preconception preparation is the “whole body”

Undergoing assisted reproduction can easily lead to number anxiety: how much AMH, how many AFC, how many eggs retrieved, how many blasts cultured, how many pass PGT… These numbers are of course important, but they are not the whole of reproductive health.

Skeletal muscle is also not merely a “fitness topic.” More and more research suggests that it may participate in women’s reproductive health through myokines, insulin sensitivity, energy metabolism, and interactions with other endocrine systems. However, current research is not sufficient to prove that “increasing muscle can directly improve egg quality or IVF success rates,” so strength training should certainly not be packaged as a so-called “shortcut to improving egg quality.”

For people who have been trying to conceive for a long time, have repeatedly tried without success, or are already preparing to enter an IVF or Thai third-generation IVF cycle, a more reasonable approach is to comprehensively evaluate age, AMH, AFC, hormone levels, ovarian response, embryo status, uterine environment, metabolic status, body fat, and muscle status together.

You do not need to develop visible abs for preconception preparation, but if you have only focused on the ovaries in the past and never paid attention to your muscle mass, body fat, and metabolic status, then this dimension is indeed worth re-examining. This is also the core point emphasized at the end: skeletal muscle participates in metabolic regulation and also shares some endocrine signaling pathways with the ovaries. The “reproductive endocrine organ” many people trying to conceive don’t know about! 4 steps to help you improve egg quality and conception…

For families planning to travel to Thailand for assisted reproduction, Huanqiu Xinsheng can provide process coordination services such as preliminary document organization, hospital appointments, doctor communication, translation accompaniment, pick-up and drop-off, and overseas medical accompaniment, helping families preparing for overseas fertility care and cross-border childbirth present their previous examinations, physical condition, and IVF treatment records to doctors more completely.

What truly needs improvement in preconception preparation has never been just a number on a lab report. The ovaries are important, but they do not work in isolation; optimizing the body’s overall state is a more complete approach to reproductive health management.