Missed Period, Negative Test: What Else It Can Be

A late period and a single white line on a test is one of the most common reasons a woman messages a gynaecologist, usually at eleven at night, usually having already tested three times.

There are two separate questions inside it, and they need answering in order. First: is the test actually right? Second: if it is right, what is stopping the period from coming?

First: can the test be wrong?

Home pregnancy tests detect hCG, the hormone the pregnancy makes. Most detect it at around 20 to 25 mIU/mL, which is usually reached a few days after implantation. The problem is that implantation does not happen on a fixed day — it is commonly around eight to ten days after ovulation, but it can be later, and in a cycle where you ovulated on day 20 instead of day 14 the whole timetable shifts.

So: if the period has not come, repeat the test in a week. If there is any doubt at all, a blood beta-hCG is definitive and gives an answer within a day. If that is negative, you are not pregnant, and the question becomes the second one.

When a late period needs investigating

One late period in a woman who is otherwise well is not usually investigated. The accepted threshold is no periods for three months in someone whose cycles were regular, or six months in someone whose cycles were already irregular. Earlier than that if you are trying to conceive, if there are other symptoms, or if you are simply worried enough that waiting is worse than testing.

Where the problem usually is

Looked at by cause, periods stopping in a woman who was previously menstruating comes from four places in roughly these proportions: the ovary in about 40% of cases, the brain's control of the ovaries in about 35%, the pituitary gland in about 17%, and the uterus or outflow tract in about 7%.

PCOS

The single commonest ovarian cause, affecting somewhere between 10 and 13% of women by current criteria. Cycles that have always been long or unpredictable, with acne, excess hair or difficulty losing weight, point to it. See PMOS and PCOS and the seven signs a doctor looks for.

Stress, weight and exercise

The brain switches off ovulation when it reads the body as not safe to conceive. Significant weight loss, a low body weight, heavy training, a crash diet, a bereavement, exam pressure, a punishing job — any of these can stop periods, and the mechanism is protective rather than broken. It is also one of the most commonly missed diagnoses, because women rarely connect the two. Periods usually return when the underlying cause is addressed, though not immediately.

Thyroid disease

An underactive or overactive thyroid disturbs cycles in both directions, and it is common here: an eight-city Indian study found hypothyroidism in roughly one adult in ten, much of it previously undiagnosed, and it is substantially commoner in women. A single TSH test finds it, and treating it usually restores the cycle. See thyroid and pregnancy.

High prolactin

Prolactin is the hormone of breastfeeding. Raised when you are not breastfeeding, it suppresses ovulation and stops periods, sometimes with milky discharge from the breasts and sometimes with no other symptom at all. Causes include a small benign pituitary growth, an underactive thyroid, and a number of ordinary medicines — some anti-nausea drugs and several psychiatric medicines raise it. It is found on a blood test and is usually very treatable.

Perimenopause, and ovaries stopping early

Cycles becoming unpredictable in the forties is usually perimenopause, and it starts earlier here than most women expect: the average age at menopause in India is around 46, against roughly 51 in Western data. Periods stopping before 40 is a different matter — premature ovarian insufficiency — and it needs confirming with repeated hormone tests, because it has implications for fertility, bone and heart health and is usually treated rather than watched.

Contraception, and coming off it

• The contraceptive injection commonly stops periods altogether, and cycles can take several months to return after the last dose.
• The hormonal coil and the implant frequently make periods light or absent. That is an expected effect, not a problem. See contraception options.
• After stopping the pill, most women have a period within a few weeks. If nothing has happened after three months, the pill was usually masking an underlying irregularity rather than causing one.
• Emergency contraception can delay or bring forward the next period by a week or so.

Breastfeeding

Periods are often absent for months while breastfeeding, particularly with frequent night feeds. This is normal — but it is not reliable contraception, and ovulation returns before the first period, so a pregnancy can start without any warning cycle.

The uterus itself

Occasionally the hormones are working and the lining cannot respond, because of scarring inside the uterus after a procedure or infection. This is Asherman's syndrome, and it is worth thinking about in anyone whose periods became scanty or stopped after a D&C, a difficult delivery or a uterine infection.

Medicines and illness

Several psychiatric medicines, some anti-nausea drugs, chemotherapy and long-term steroids all affect cycles, as do poorly controlled diabetes, coeliac disease, tuberculosis and any serious illness. Do not stop any prescribed medicine because of this — bring the list to the appointment instead.

The tests that sort it out

The first-line set is short and answers most cases: a pregnancy test, TSH, prolactin, and FSH with oestradiol. Depending on the picture, testosterone and related hormones are added when PCOS is suspected, and a pelvic ultrasound looks at the ovaries and the thickness of the lining. Scans are arranged by referral.

When not to wait

• Severe or one-sided pelvic pain, with or without a positive test — this is the ectopic pregnancy question, and it is a same-day problem.
• A positive test with bleeding or pain.
• Milky discharge from the breasts, headaches or changes in your vision, which point to the pituitary.
• Periods stopping before 40.
• Rapid weight change, severe hair loss, or feeling unwell with it.

What happens at the clinic

Consultation, the pregnancy test, and the blood tests above all happen at the clinic, along with treatment once the cause is clear — thyroid treatment, managing high prolactin, PCOS management, hormone treatment where it is needed, or help with conceiving. Scans are arranged by referral.

Bring the dates of your last three or four periods if you have them, or the app. It is the single most useful thing you can arrive with, and it frequently answers the question before any test is done.