Life stage · After having a baby
After birth, the NHS checks your baby thoroughly and you almost not at all. The six-week check rarely includes a blood test, and yet the months after delivery are when four things go wrong in the blood at once: iron stores emptied by the birth itself, a thyroid that can swing over- then underactive in the first year, B12, folate and vitamin D depleted by nine months of building a person and then feeding one, and blood sugar that needs rechecking if you had gestational diabetes. Every one of those looks like "just tiredness" and every one of those is treatable. This is what to test, when, and what the result means.
A phlebotomist comes to your house, so no clinic trip with a newborn. Report within 48 hours of the lab receiving your sample.
Last reviewed 16 September 2026
The short answer
A postnatal blood test should cover ferritin and full iron studies with a blood count, a full thyroid panel with antibodies, B12, folate and vitamin D, and HbA1c if you had gestational diabetes or a large baby. Take it six to twelve weeks after birth, and again at six months if the first result showed anything or if new tiredness, low mood or hair loss arrive later, which is when postpartum thyroiditis usually declares itself. If you are breastfeeding, all of it is safe and nothing needs to change.
Educational, not a substitute for your GP, midwife or health visitor. Thoughts of harming yourself or your baby, or feeling unable to cope, need help today: your GP, 111, or the PANDAS helpline. A blood test is part of the picture, never the whole of it.
What to test
| Marker | Why it goes wrong after birth | What to look for | NHS checks it? | Panel |
|---|---|---|---|---|
| Ferritin, iron studies, haemoglobin | Pregnancy uses around a gram of iron and delivery loses more; a caesarean or a haemorrhage loses much more. Low iron causes exhaustion, breathlessness, poor concentration, low milk supply and low mood, and it is the single commonest postnatal finding | Ferritin below 30 is deficiency; symptoms common below 50; haemoglobin below 110 g/L is postnatal anaemia | Haemoglobin only, and only if you bled heavily | All panels |
| Thyroid (TSH, free T4, free T3, TPO antibodies) | Postpartum thyroiditis affects around 1 in 20 women: an overactive phase at 1 to 4 months (anxiety, palpitations, weight loss, insomnia) then an underactive phase at 4 to 8 months (exhaustion, weight gain, low mood, hair loss). Women with TPO antibodies or type 1 diabetes are at much higher risk | TSH suppressed early, then raised; free T4 out of range; positive TPO antibodies predict it | No, unless you ask and describe symptoms | All panels |
| B12 and folate | Both are drawn on heavily by the baby in pregnancy and by breastfeeding; low B12 causes fatigue, low mood, pins and needles and brain fog, and is common in vegetarian and vegan mothers | B12 below 300 pmol/L is a grey zone worth treating with symptoms; folate low | No | All panels |
| Vitamin D | Transferred to the baby in pregnancy and through milk; near-universally low in UK mothers in winter. Low vitamin D is associated with postnatal low mood and with bone loss during breastfeeding | Below 50 nmol/L insufficient; aim above 75, particularly if feeding | No | All panels |
| HbA1c | Gestational diabetes carries a high lifetime risk of type 2; NICE recommends an HbA1c 6 to 13 weeks after birth and then yearly, and a large proportion of women never get it | HbA1c 42 to 47 is prediabetes; 48 or above is diabetes; anything above 38 is worth watching | Supposed to, after gestational diabetes; often missed | All panels; fasting insulin in Ultimate and Signature |
| hs-CRP | Slow-healing wounds, mastitis, retained products and endometritis all show as inflammation; so does the low-grade picture behind persistent fatigue | Above 3 mg/L at six weeks or later is worth explaining, particularly with pain, fever or discharge | No | All panels |
Thresholds are UK laboratory conventions, NICE and BSH guidance. Your report reads each result against the others. Guides: ferritin, thyroid, B12, vitamin D, HbA1c, hs-CRP.
Low mood after birth
Postnatal depression is real, common and treatable, and it is not caused by a blood result. But three of the markers above produce symptoms that are indistinguishable from it: iron deficiency (exhaustion, low mood, poor concentration, tearfulness), the underactive phase of postpartum thyroiditis (the same, plus weight gain and hair loss, typically at four to eight months, which is exactly when postnatal depression is often diagnosed), and low B12 or vitamin D. A woman treated for postnatal depression with a ferritin of 12 or a TSH of 9 will not get better until those are corrected. That is not an argument against treatment for depression. It is an argument for checking the blood before assuming the cause. If you are struggling, tell your GP or health visitor now and get the bloods done alongside; the two are not in competition. The blood tests behind anxiety.
Read it in context
6 to 12 weeks
Ferritin under 30, haemoglobin at the low end, folate and vitamin D low, everything else fine. This is the birth itself and it is the commonest picture. Iron at the right dose, folate and vitamin D, and a retest at three months. Most women feel the difference within six weeks.
3 to 6 months
TSH suppressed with a high free T4 and anxiety, or TSH raised with a low free T4 and exhaustion, with TPO antibodies positive. Postpartum thyroiditis. It usually settles within a year but the underactive phase often needs treating, and about a quarter of women are left with a permanently underactive thyroid, so it needs a GP and follow-up. Thyroid guide.
After gestational diabetes
HbA1c at 41, fasting insulin raised. Not diabetes, but the direction is clear and this is the window where diet, movement and, later, weight make the difference. NICE says test yearly for life; a panel with insulin shows the trend earlier than HbA1c alone. Prediabetes blood test.
Which panel
The postnatal panel
Advanced
74 biomarkers · £269
Ferritin with full iron studies and blood count, full thyroid with antibodies, B12, folate, vitamin D, HbA1c, hs-CRP, plus liver, kidney and core hormones. Every marker in the table, in one draw.
View AdvancedUltimate
114 biomarkers · £349
Adds fasting insulin and HOMA-IR after gestational diabetes, the complete hormone set including prolactin and progesterone, and cystatin C. For the mother who wants the full picture or is planning another pregnancy.
View UltimateHealth plans
2, 3 or 4 tests · from £506
The 6-to-12-week test and the 6-month retest bought together at a lower price per test, with the second report compared against the first.
View health plansAt-home draw £39, clinic £19. Safe while breastfeeding. Fasting is only needed for insulin; if you are feeding overnight, tell us and book Advanced without fasting. Pay monthly available.
Honest comparison
The six-week postnatal check is a conversation about recovery, contraception, mood and the baby, and it is valuable. It is not a blood test. Haemoglobin is checked on the ward if you bled heavily, and gestational diabetes is meant to trigger an HbA1c at 6 to 13 weeks, but audit after audit shows a large proportion of women never receive it. Ferritin, thyroid, B12, folate and vitamin D are not on any routine postnatal pathway at all. If your GP will run them, ask; it is free and this page tells you what to ask for. If they will not, or the appointment is weeks away, a panel drawn at home with the baby asleep is the practical route, and the report tells you which results to take back to the GP. What to ask your GP for.
After your result
Each marker explained against the others, in plain English, with the birth and feeding context built in. Reviewed by a medical professional before it reaches you.
Iron, B12, folate and vitamin D are corrected with supplements at the right dose, all compatible with breastfeeding. A thyroid result or a raised HbA1c needs a prescriber and follow-up, and the report tells you which results to show them.
Iron takes about three months to refill, and six months is when the underactive phase of postpartum thyroiditis appears. The second report catches both. Retest plans.
FAQs
Ferritin with iron studies and a blood count, a full thyroid panel with antibodies, B12, folate, vitamin D, hs-CRP, and HbA1c if you had gestational diabetes or a large baby. All are in the TrueVitals Advanced panel.
Six to twelve weeks after birth for the first one, when the acute changes of delivery have settled and the iron picture is clear. A second at around six months catches the underactive phase of postpartum thyroiditis and confirms nutrient stores have refilled.
Yes, with no effect on milk or the baby. The only adjustment is fasting: it is needed for fasting insulin (Ultimate) but not for the Advanced panel, so if you feed overnight, book Advanced and eat normally.
Both. Broken sleep is unavoidable; exhaustion out of proportion to it, breathlessness on stairs, hair loss, feeling cold, or low mood that does not lift are the signs the blood is part of the problem. Iron deficiency and postpartum thyroiditis are both common and both routinely missed.
Inflammation of the thyroid in the first year after birth, affecting around 1 in 20 women and far more of those with TPO antibodies. It typically causes an overactive phase at one to four months and an underactive phase at four to eight months; most recover, but about a quarter stay underactive. It is diagnosed with TSH, free T4 and antibodies and is usually missed because nobody tests for it.
Yes, and most new mothers do. A registered phlebotomist comes to your house for £39 and takes the same venous sample a clinic would, in about ten minutes. Morning slots are available. How at-home testing works.
Advanced and Ultimate reports are delivered within 48 hours of the laboratory receiving your sample. Signature takes around 12 working days.
Every postnatal marker in one draw, at home with the baby, with a report within 48 hours that says what is low, why, and what to do about it.
Hair loss · Always tired · Anxiety · Blood tests for women · Find a clinic
.png)