Updated: Apr 5
Women’s hormones are constantly shifting and changing, and some of these changes can be mapped out fairly predictably each decade. One of the most important shifts in the 30’s is that your health and hormones are more reactive to stress levels, poor diet, lack of sleep, alcohol and caffeine than in the 20’s, meaning you can’t quite get away with as much without some consequence.
1. Estrogen, progesterone and testosterone are still cycling in a predictable pattern
The length and flow of your period should regular, and ideally somewhere between 27-31 days apart. As you reach your late 30’s, cycles may start coming a little closer together (25-27 days apart).
2. Fertility rates are still good
In most cases, fertility is still quite good through to age 38 or so, as long as your cycles have been quite consistent through this decade. The onset of age-related hormone changes affecting fertility however can vary, and in some cases begin as early as 35. One potential issue with delaying fertility to the mid or late 30’s is that if there are fertility difficulties related to endometriosis, immune issues, PCOS or others, there is a shorter window with good egg quality in which to treat it. That’s why it is generally recommended to start trying to conceive before age 35.
3. Miscarriage rates steadily go up through the 30’s
Miscarriage rates are fairly low under age 35, estimated at less than 15% (after ultrasound confirmed pregnancy). This number approximately doubles by age 40, climbing steadily through the late 30’s to 29% at age 40. (1). The reality is that our eggs are aging, even if we feel healthy and fit.
4. Unaddressed hormone imbalance will become more problematic
It’s very common for women to come off birth control in their 30’s in order to get pregnant. If there was a hormone imbalance, or hormone=related condition such as endometriosis, PCOS, fibroids, or others they may be more problematic now if you the underlying causes have not been addressed. Also, conditions such as endometriosis tend to progress and worsen with time (unless they are treated), and can be more symptomatic in the 30’s than in the decades previous.
5. Prolonged periods of high stress can result in weight gain
Stress levels can be higher in the 30’s with career, relationship and family demands. Persistent high stress will cause a raise in cortisol that can contribute to weight gain, especially weigh held around the central abdomen. High cortisol levels can also affect sleep, food cravings and increased anxiety.
6. PMS levels can get worse
There are several things that can cause PMS to get progressively worse: first, progesterone levels begin to drop in the mid to late 30’s, creating a relative hormone imbalance and more moody PMS periods. And secondly, lifestyle factors such as lack of sleep, too much caffeine, alcohol and a busy life can catch up to you. Think of the PMS window of yrou cycle as a time where the amplification is turned up on things that are out of balance.
7. Insulin resistance – unhealthy habits start to catch up to you
In your 30’s, you’ll probably notice that you can’t eat whatever you want without consequence. Metabolism may slow slightly, but more importantly if there is any susceptibility for blood sugar imbalance especially insulin resistance, the consequences will begin to become noticable with increased sensitivity to eating too many carbohydrates. This is a time where moderation pays off, and large high-carb meals are no longer ideal.
Overall, with a little extra care and attention to a healthy lifestyle, you can maintain excellent hormone balance, metabolism and vitality through your 30’s.
Stay tuned for upcoming articles on Hormone Changes in your 40’s and 50’s.
Nybo Andersen AM, Wohlfahrt J, Christens P, Olsen J, Melbye M. Maternal age and fetal loss: population based register linkage study. BMJ. 2000 Jun 24; 320: 1708-1712.