Pregnancy symptoms: early signs and when to take a test

These are the early pregnancy symptoms described by the federal Office on Women's Health (OWH). Not everyone gets them, and they can show up in any order:

To be honest: early pregnancy symptoms look a lot like the days before a period. Tender breasts, tiredness, headache and mood swings happen in both. So no symptom on its own confirms pregnancy. The only way to know is a pregnancy test, which looks for the pregnancy hormone hCG (human chorionic gonadotropin) in urine or blood.

What about pregnancy symptoms in the first week? According to OWH, hCG is made once a fertilized egg implants in the uterus. So in the first week after sex, there is not yet any hCG for a test to detect. Some early signs, like headache, tiredness and breast tenderness, can show up even before a missed period.

If your period is late and the test is negative more than once, read about a late period when you are not pregnant: stress, weight changes and some thyroid conditions can delay it too.

According to the FDA, a home pregnancy test gives the most reliable result 1 to 2 weeks after your missed period. Some brands can detect pregnancy before a missed period, but if you test too early there may not be enough hCG yet, and the test can be negative even if you are pregnant. First-morning urine usually has the most hCG.

How to read a pregnancy test: - Follow the box instructions exactly and check the expiration date. - If the control line or symbol doesn't appear, the test didn't work: don't trust the result, and repeat it with a new test. - Positive pregnancy test: it usually means you are pregnant. Talk to a doctor to confirm it and start your care. - Negative test: treat it as tentative. If you tested early, repeat it in a week. If you get two negatives and still think you are pregnant, see a doctor.

Until you are sure, the FDA advises acting as if you could be pregnant: avoid alcohol and smoking, and don't take medicines without checking first.

A blood pregnancy test picks up hCG sooner than urine: about 10 days after conception, compared with typically 2 weeks or more for a urine test. There are two kinds:

• Qualitative: tells you whether hCG is there or not. It is about as accurate as a urine test.
• Quantitative (beta hCG): measures the exact amount of hCG in your blood, in mIU/mL. It helps estimate how far along you are and track how the hormone rises.

According to MedlinePlus, people who are not pregnant usually have less than 5 mIU/mL. In pregnancy, hCG rises quickly during the first trimester. A lower-than-expected level can point to an ectopic pregnancy or a miscarriage, and a higher one to twins or other conditions; ranges vary a little from lab to lab. That is why the number is read with a doctor, and sometimes the test is repeated to see how it changes.

After a video visit, the doctor gives you a lab order for a quantitative hCG test at a lab near you. No special preparation is needed: it is a blood sample from a vein. When your result is ready, she goes over it with you in a follow-up visit.

You see Dr. Diana Nieves Castro by video. She is a general practice physician licensed in Puerto Rico with several years of emergency-department experience. She goes over your symptoms, the date of your last period and your home test result, gives you a lab order for a blood pregnancy test and reviews the result with you.

If you are pregnant, she reviews the medicines you take and your health conditions, and refers you to an OB-GYN to start prenatal care. If you don't want to get pregnant, she walks you through your birth control options.

We see patients of all ages. For patients under 21, a parent or legal guardian stays on camera for the whole visit and shows photo ID. You need to be physically in Puerto Rico during the visit.

Video doctor visits 24/7: book online and choose your time right away.

• Start prenatal care with an OB-GYN. The doctor can refer you.
• Folic acid: the CDC recommends 400 mcg of folic acid every day for anyone who could become pregnant, before and during early pregnancy, to help prevent neural tube defects (of the baby's brain and spine).
• Review your medicines with a doctor, including over-the-counter medicines and supplements. Don't suddenly stop a prescribed medicine without talking it over first.
• Avoid alcohol and smoking.

Zika is spread by mosquitoes in Puerto Rico and can affect a baby: read about Zika and pregnancy.

If you had unprotected sex in the last few days, the morning-after pill can still help: the sooner, the better. According to the FDA, it does not end a pregnancy that has already started; if your test is already positive, talk with the doctor. Going forward, the doctor can talk you through birth control by video and, if appropriate, prescribe a method.

According to MedlinePlus, if you are pregnant and have any vaginal bleeding, with or without cramping, contact a doctor. Light bleeding doesn't always mean something is wrong, but it needs to be checked.

Go to the ER or call 911, and don't book a video visit, if you have severe, sudden pain in the lower belly (especially on one side), heavy bleeding, fainting or shoulder pain. These can be signs of a ruptured ectopic pregnancy, which is an emergency. See also emergencies.