{"id":29014,"date":"2026-09-24T00:11:50","date_gmt":"2026-09-23T22:11:50","guid":{"rendered":"https:\/\/www.badania-medyczne.pl\/?p=29014"},"modified":"2026-10-20T13:10:29","modified_gmt":"2026-10-20T11:10:29","slug":"hormonal-contraception-blood-tests-before-and-during-use","status":"publish","type":"post","link":"https:\/\/www.badania-medyczne.pl\/en\/hormonal-contraception-blood-tests-before-and-during-use\/","title":{"rendered":"Hormonal contraception: which blood tests to have before and during use"},"content":{"rendered":"

Hormonal contraceptives (pills, patches, vaginal rings, injections, implants and hormonal coils) are among the most thoroughly studied groups of medicines. This does not mean they have no effect on the body: oestrogens and progestogens affect blood clotting, the liver, lipid and carbohydrate metabolism, and blood pressure. It is therefore worth having several blood tests both before starting and during use. Below, we explain which tests matter, why, and how often to repeat them. Your gynaecologist decides on the contraceptive method; the tests help ensure it is safe.<\/p>\n

Why tests before starting contraception matter<\/h2>\n

The greatest risk associated with preparations containing oestrogen is venous thromboembolism. It is rare, but the risk increases several-fold in women with inherited thrombophilia, those who smoke after the age of 35, and those with obesity or migraine with aura. Some of these factors are identified through your medical history, others only through blood tests. The second area is the liver, which metabolises hormones; the third is lipid metabolism and glucose, because oestrogens raise triglycerides and progestogens may reduce insulin sensitivity.<\/p>\n

Tests before starting contraception<\/h2>\n

Full blood count<\/h3>\n

A basic screening test: it rules out anaemia (common with heavy periods) and platelet disorders, which affect blood clotting.<\/p>\n

Liver function tests: ALAT, ASPAT, GGT, bilirubin<\/h3>\n

Active liver disease is a contraindication to oestrogen-containing contraception. Normal liver function tests before starting provide a baseline for later checks.<\/p>\n

Lipid profile and glucose<\/h3>\n

Total cholesterol, LDL, HDL, triglycerides and fasting glucose. High triglycerides or abnormal blood glucose do not rule out contraception, but they affect the choice of preparation (e.g. methods without oestrogen) and how often checks are needed.<\/p>\n

Blood clotting<\/h3>\n

Standard tests: activated partial thromboplastin time (APTT), PT (INR), fibrinogen and, potentially, D-dimer. A full thrombophilia work-up (factor V Leiden mutation, prothrombin gene mutation, protein C, protein S, antithrombin and antiphospholipid antibodies) is not recommended for every woman, but makes sense if there is a family history of thrombosis, pulmonary embolism, strokes at a young age or recurrent miscarriages. It is worth discussing these tests with your doctor before having them, as their interpretation is complex.<\/p>\n

Thyroid-stimulating hormone (TSH)<\/h3>\n

Thyroid disorders are common in women and affect the menstrual cycle as well as body weight and mood; these symptoms can easily be mistaken for \u201cside effects of the pill\u201d. Testing TSH before starting contraception helps avoid incorrect conclusions.<\/p>\n

Prolactin<\/h3>\n

Oestrogens can slightly raise prolactin levels. A baseline result makes assessment easier if you develop milky nipple discharge, headaches or visual disturbances during use.<\/p>\n

Blood pressure and BMI<\/h3>\n

These are not blood tests, but they are part of standard assessment: blood pressure above 140\/90 mmHg and a BMI above 30 change the balance of benefits and risks of combined contraceptives.<\/p>\n

Tests during use<\/h2>\n

It is worth repeating liver function tests and a lipid profile 3\u20136 months after starting, then checking them once a year, together with a full blood count, glucose and blood pressure. For women with risk factors (being overweight, smoking or a family history of diabetes), the doctor may recommend more frequent checks and additional HbA1c or fasting insulin tests. Annual cervical screening and a gynaecological examination remain separate from blood tests.<\/p>\n

How contraception affects test results<\/h2>\n

This is important when interpreting results of tests performed for other reasons. Oestrogens increase levels of hormone-binding proteins, so TSH may be slightly different, while total thyroxine (T4) and total cortisol are raised despite normal free hormone fractions. SHBG increases, which lowers free testosterone (this is why the pill improves acne). FSH, LH and oestradiol do not reflect the activity of your own ovaries: measuring them while using contraception serves no purpose unless your doctor advises otherwise. CRP, fibrinogen and triglycerides also increase; vitamin B12 and folate (folic acid) decrease slightly. The doctor interpreting the result should know that you are using hormones.<\/p>\n

Symptoms that require immediate medical attention<\/h2>\n