You stop ovulating when your Body Mass Index (BMI) is too low (under 18.5) or too high (obese), disrupting the hormonal balance needed for regular ovulation, with significant risks starting around BMI 27. Being underweight (BMI < 18.5) or overweight/obese (BMI > 27) can cause irregular cycles or stop ovulation altogether, impacting fertility, so aiming for a healthy BMI (around 18.5-24.9) is key, though individual factors matter.
A BMI of 18.5 or less (underweight) may cause irregular menstrual cycles and may cause ovulation (release of an egg from the ovaries) to stop. A BMI of 17.5 or less may indicate an eating disorder. Women at less than normal BMI should talk with their doctor about exercise, nutritional or hormonal issues.
But the good news is that even moderate weight loss can positively impact fertility for women. Providers recommend that those hoping to become pregnant lose 5% to 10% of excess weight to restore normal reproductive functioning. This is often enough to improve your chances.
There are also several factors that can affect fertility. These include: age – fertility declines with age. weight – being overweight or obese (having a BMI of 30 or over) reduces fertility; in women, being overweight or severely underweight can affect ovulation.
The ideal weight for conception depends on how tall you are. Your body mass index (BMI) is a number based on your height and weight. The healthy BMI range is between 18.5 and 24.9. Adults with a BMI between 25 and 29 are considered overweight and a BMI over 30 indicates obesity.
Being overweight or obese may affect your fertility. This means that it may make it harder to get pregnant. Bringing your BMI down before you get pregnant, even by one or two points, will help reduce your risk of complications.
Women with a body mass index (BMI) above 27 are three times more likely than women in the normal weight range to be unable to conceive because they don't ovulate. Women who are overweight or obese are much less likely to conceive.
Ovulation problems can be a result of:
If you are overweight or obese:
Being overweight may not increase your risk of having problems with ovulation, but obesity (BMI greater than 30) increases the risk of having abnormal ovulation and menstrual cycles. Obesity makes it more likely that it will take longer for you to get pregnant.
For men, some of these signs include a healthy sperm count, high-quality sperm that can swim quickly and easily, and a good balance of hormones. For women, good fertility indicators include regular ovulation, the presence of cervical mucus, and the regularity of menstrual cycles.
The 3-3-3 rule for weight loss is a simple, habit-based method focusing on three key areas: 3 balanced meals a day, 3 bottles (or ~1.5L) of water by 3 PM, and 3 hours of physical activity per week, aiming for consistency over complex diets. It simplifies fat loss by establishing rhythm through consistent eating, adequate hydration to support metabolism, and regular movement, promoting sustainable health without intense calorie counting or restrictive rules, says Five Diamond Fitness and Wellness, Joon Medical Wellness & Aesthetics, and EatingWell.
Generally speaking a “normal” female BMI is 18 - 25 but because being too light can impact a person's ability to conceive, the ideal range for hopeful parents is 20 - 25.
The 7 key signs of ovulation include changes in cervical mucus (becomes clear, stretchy like egg whites), a slight rise in basal body temperature, mild one-sided pelvic pain (mittelschmerz), increased libido, breast tenderness, bloating, and sometimes light spotting, all driven by hormonal shifts that signal your most fertile window.
Ozempic is typically recommended for individuals who have a BMI of 30 or higher, which falls into the obese category, or for those with a BMI of 27 or higher who have additional health concerns such as high blood pressure, type 2 diabetes, or high cholesterol.
Research has shown that most women need a body fat percentage of around 22% to maintain regular menstruation. When body fat dips below this level, the body reduces its production of estrogen in defense against starvation. This is why eating disorders, such as anorexia nervosa or bulimia, can cause missed periods.
Suboptimal conditions during the oocyte maturation stage can negatively impact further embryo development [31]. Obesity may affect oocyte competence and maturation through alterations in various hormones, particularly those hormones that trigger oocyte maturation.
Early testing for gestational diabetes.
For people at average risk of gestational diabetes, a screening test called the glucose challenge often is done between weeks 24 and 28 of pregnancy. If you have a BMI of 30 or higher, your healthcare professional might recommend the screening test at your first prenatal visit.
Excess physical or emotional stress, a very high or low body weight, or a recent substantial weight gain or loss can disrupt this pattern and affect ovulation. The main sign of hypothalamic dysfunction is irregular or absent periods and often low estrogen levels.
When you don't ovulate, there's no egg to fertilize. Because of this medical definition, you technically can't menstruate without ovulating. However, you can still bleed — experience a “period” — without ovulating. This is known as abnormal uterine bleeding (AUB), or anovulatory bleeding.
You know you might be infertile (or facing fertility issues) primarily by the inability to get pregnant after a year (or six months if over 35) of regular, unprotected sex, but symptoms in women can include irregular/painful periods or no periods, while men might have issues with sexual function, hair growth, or testicular pain, all signaling a need for medical evaluation with tests like blood work or ultrasounds.
As women “use up” the eggs they were born with, by age 40, many women deplete their ovarian reserve and have difficulty producing enough good-quality eggs to make it to implantation, even with stimulation.
Key takeaways. Technically, it only takes one sperm to get pregnant. But the chances are higher when your partner's ejaculate contains at least 15 million sperm per milliliter.
Being overweight or obese
The excess oestrogen can affect how often you have periods, and can also cause your periods to stop. Your GP may refer you to a dietitian if you have a BMI of 30 or more and it's affecting your periods. The dietitian will be able to advise you about losing weight safely.