Vitamin D Deficiency in Women: Impact on Fertility & Health

The short answer: Most Indian women are low on vitamin D, with large studies finding roughly 7 to 9 out of every 10 people deficient, even in our sunny country. The reasons are darker skin needing more sun, indoor life, covering up, city smog, and a diet with almost no vitamin D. A simple blood test tells you where you stand. The fix is usually some sun, better food, and a doctor-guided supplement. This guide gives you the real numbers, honest answers about PCOS and fertility, and exactly how to correct it.

How common is vitamin D deficiency in Indian women?

Very common. Most large Indian studies find that roughly 7 to 9 out of every 10 people have low vitamin D, and the average level sits below what is considered healthy. A review of 40 studies covering nearly 20,000 healthy Indians found the average blood level was only about 14, when above 30 is the healthy target.

Women tend to test a little lower than men, and levels drop further with city living and in winter. You will see different numbers quoted (some say 70 percent, some say 90), and that is simply because studies test different groups and use different cut-offs. The one clear message across all of them: low vitamin D is the normal state for most Indian women, not a rare problem.

Why are Indians deficient when we have so much sun?

This is the question everyone asks. Sunlight alone is not enough here, for several real reasons stacked on top of each other.

Darker skin needs longer in the sun to make the same vitamin D. Most of us work indoors, cover our arms and legs, and avoid the harsh midday heat, which is exactly when the useful rays are strongest. City smog blocks those rays. And our food carries very little vitamin D, because it is found mostly in animal foods, while a large share of Indians eat vegetarian. On top of all this, India barely fortifies foods with vitamin D.

How do I know if I am deficient?

A simple blood test called 25-hydroxy vitamin D tells you. Below 20 is deficient, 20 to 30 is borderline-low, and above 30 is considered healthy. Ask your doctor for this test if you have symptoms or if you are planning a pregnancy.

The symptoms are real but non-specific, meaning they can point to many things: aching bones or muscles, tiredness that does not lift, low mood, hair fall, and catching every cough and cold. Many people have no symptoms at all, which is why a blood test is the only way to be sure. Do not self-diagnose from a tired week.

What does vitamin D actually do for me?

Its most proven job is bone health. Vitamin D lets your body absorb calcium from food. Without enough of it, your bones cannot take up calcium properly, so over time they soften and ache, and the risk of weak bones (osteoporosis) and fractures rises, especially as you get older. This part of the science is rock-solid.

Where the science is weaker, I want to be honest with you, because there is a lot of exaggeration online.

Claim	What the evidence really shows
Bones and calcium	Strong and proven. Deficiency softens and weakens bones.
PCOS	Low vitamin D is common in PCOS and travels with insulin problems, but correcting it is not proven to cure PCOS.
Fertility and pregnancy	Healthy levels are linked to smoother pregnancies, but vitamin D is not a proven fertility booster.
Immunity	It supports your defences; the very deficient may benefit, but a daily pill is no shield for someone with normal levels.

Vitamin D and PCOS: the honest picture

Low vitamin D turns up in more than half of women with PCOS (around 58 percent), and it travels alongside insulin problems and weight. That makes it worth checking and correcting. But topping up vitamin D has not been shown to fix PCOS. Treat it as one piece to put right, not a cure. The core of PCOS care is still diet, movement and the right tests, which I cover in my PCOS diet guide.

Vitamin D and fertility: the honest picture

Women with healthy vitamin D tend to have smoother pregnancies, and correcting a deficiency in pregnancy is sensible. With fertility treatment the results are mixed and uncertain. But vitamin D is not a proven fertility booster, so please do not expect a pill alone to help you conceive. If you are trying for a baby, my natural fertility guide covers what genuinely helps, starting with folic acid.

How much sun, food and supplement do I need?

India's own guideline recommends 600 units of vitamin D a day for adults, and 800 after age 60. It also reminds people that everyday time outdoors matters. Vitamin D comes to you three ways.

Sun: getting your arms and legs into the sun for a short spell around midday, three times a week, is roughly what our own researchers say you need. Darker skin and city smog mean you may need a bit more. For many women, sun alone will not be enough.

Food: the richest sources are fatty fish, egg yolk, and fortified milk, with small amounts in mushrooms. If you eat vegetarian, your food gives you very little, which is why supplements often matter more.

Supplement: this is the reliable route for most deficient Indians. But get tested first and let your doctor set the dose.

How is a deficiency corrected?

In India, the usual correction is a 60,000 unit sachet taken once a week for about 8 to 12 weeks, then a monthly top-up to maintain. But this is a doctor's decision, made after a blood test, not something to buy and swallow on your own guesswork.

Why the caution? Vitamin D is very safe at normal doses. You would have to take huge amounts for months to get into trouble. But that is exactly why people harm themselves: they keep taking high-dose pills for months without testing, and levels climb too high. Test, correct with your doctor, then retest. That is the safe loop.

Your questions, answered

Why is vitamin D deficiency so common in India despite the sun?

Because sunlight alone is not enough here. Darker skin needs more sun to make vitamin D, most of us stay indoors or cover up, city smog blocks the useful rays, our food carries very little vitamin D, and India barely fortifies foods with it. All these stack up, so most Indian women end up low.

What are the symptoms of low vitamin D in women?

Aching bones or muscles, tiredness that does not lift, low mood, hair fall, and frequent coughs and colds. These can all mean other things too, so they only hint at low vitamin D. A blood test is the only way to confirm it.

Can vitamin D help me get pregnant or fix PCOS?

Correcting a deficiency is sensible and part of good health, but vitamin D is not proven to cure PCOS or to boost natural fertility on its own. It is one piece to put right, alongside diet, weight and the proper tests. Do not rely on it as a treatment by itself.

How much vitamin D should I take daily?

India's guideline recommends 600 units a day for adults, and 800 after age 60, from all sources. If you are already deficient, correcting it needs a higher, doctor-guided dose for a few weeks, decided after a blood test. Do not self-prescribe high-dose pills for months.

Is it safe to take vitamin D without a test?

A normal daily dose is safe. The danger comes from taking high-dose pills for months without testing, which can push your levels too high. The safe approach is to test first, correct with your doctor, and retest.

Sources for this article (8)

1. Systematic Review on Vitamin D Level in Apparently Healthy Indian Population, Indian J Endocrinol Metab, 2017 (accessed July 2026)
2. Vitamin D deficiency in India, J Family Med Prim Care, 2018 (accessed July 2026)
3. Vitamin D Deficiency, StatPearls (thresholds, symptoms, bone effects) (accessed July 2026)
4. ICMR-NIN, Nutrient Requirements for Indians (RDA), 2020 (accessed July 2026)
5. Prevention and Treatment of Vitamin D Deficiency in India (Consensus), Indian J Endocrinol Metab, 2025 (accessed July 2026)
6. Harinarayan et al., Vitamin D status and sun exposure in India, Dermato-Endocrinology, 2013 (accessed July 2026)
7. Vitamin D deficiency prevalence in PCOS, Frontiers in Nutrition, 2026 (accessed July 2026)
8. Vitamin D toxicity from overcorrection, Nutrients, 2018 (accessed July 2026)

This article is for your information and learning. It is not a substitute for a consultation. For advice about your own health, talk to me or your own doctor.