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Barbara Dehn, RN, MS, NP, FAANP, NCMP

Practicing Nurse Practitioner


San Francisco, CA

Barbara Dehn, RN, MS, NP, is a practicing nurse practitioner and a television health expert, who's known as Nurse Barb. She's passionate about health education, whether it's 1 on 1 with a patient, in a lecture hall at Stanford or with millions of people watching on television. Her warm and engaging personality puts everyone at ease as they learn more about health.

Nurse Barb is the award winning author of the Personal Guides to Health used by over 5 million women in the US, with titles ranging from fertility and pregnancy to menopause and breastfeeding. Active in Social Media, she contributes content to HealthyWomen, Huffington Post, NurseBarb, KevinMD and The Patch and amplifies her reach with an active and engaged Facebook following and 34,000 Twitter followers.

She is the author of The Hot Guide to a Cool Sexy Menopause, Nurse Barb's Guide to Breastfeeding and Nurse Barb's Guide to Pregnancy.

Barb earned a masters degree from UCSF and a BS from Boston College. She's certified by the North American Menopause Society and is a Fellow in the American Association of Nurse Practitioners. Over the last 2 years, she's been an active participant in Global Health Initiatives at FAME Hospital in Karatu, Tanzania. Barb lives in the San Francisco Bay area.

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When Did I Get Pregnant?
When Did I Get Pregnant?

When Exactly Did I Get Pregnant?

If you want to find out exactly when you got pregnant, talk with your health care provider. You may not be able to pinpoint the day, but you can usually narrow it down to a week.


This is a call I get all the time: Help! When exactly did I get pregnant?

Usually the person on the other end of the phone is in panic mode and overwhelmed, needing answers right away.

First, you're not alone. If you need to know exactly when you got pregnant, you probably have good reasons for trying to figure this out. Many women need to know right away.

Even if the circumstances surrounding this conception were not ideal, it's important to take a few slow deep breaths so that you can think clearly. Then, make sure that you're pregnant by taking a urine pregnancy test, if you haven't already. Find out if it's a real issue and not just something that you're worried could be happening.

If you have had a positive pregnancy test and you're worried about exactly when you conceived, you'll want to discuss this with your health care provider. To get the information you need from them, there are a few things you need to write down and bring to your appointment.

(Click to watch my "When Did I Get Pregnant" video.)

What You Need to Know

  • What was the first day of your last menstrual period?

  • Were you using any form of contraception? If so, which ones and when? Did you stop the pill or forget about taking it? Remove the ring? Experience a condom break? It is important to recall if any of those things happened.

  • Did you use any form of emergency contraception? If so, when and what happened?

  • When did you have intercourse?

  • Is there anything else you're worried about, such as use of medications, alcohol or drugs? If so, how much and when?

  • Are you concerned about who the father is? If so, it's helpful to know when you were intimate with each partner.

What to Expect From Your Health Care Provider

Your provider may want to repeat the pregnancy test and, if it's positive, will want to do an exam and possibly an ultrasound to help date the pregnancy. One thing you'll hear from your provider is that even with very sophisticated technology like ultrasounds that can give a fairly accurate idea of how far along a woman is, these have a plus or minus of three to seven days of variation. They're good, but they can't pinpoint conception to the hour or day.

Up to a Week of Uncertainty

We know that when a woman ovulates, the egg lives in her Fallopian tube for about 24 hours. Yet, we still can't predict exactly the day or time that a woman got pregnant for a few reasons: Not every woman ovulates and produces an egg exactly two weeks after the first day of her period. And, unless you're tracking ovulation with basal body temperature charts or urine luteinizing hormone tests, knowing when you ovulated may be, at best, a guess. Visit HealthyWomen's ovulation calculator.

Male Factor

To make it even more difficult to pinpoint the exact date of conception, sperm can live up to five days before meeting up with an egg. Here's a scenario to help explain: If a woman has sex on a Saturday night, the sperm can live in her body just waiting for the egg to be released on Wednesday. If she has intercourse again on Monday or Tuesday, it's impossible to know which time led to the pregnancy.


If a woman is worried about determining exactly when she conceived, she may also be concerned about who the father of the baby is. In many cases, health care providers can't give 100 percent guarantees without genetic testing during the pregnancy or blood tests after the baby's born.

Medications, Drugs and Alcohol

Many women want to know when they conceived because of concerns about exposures to drugs and alcohol. If these are your concerns, it's important to know that if exposures to any of these occurred before the period was missed, in the first 10 days after conception, the likelihood is that there was no effect.

However, with certain medications or long-term use of drugs or alcohol, there can be effects, so it's best to discuss this with your health care provider because each woman and each situation is different.

In any case, remember to gather the information you need and then see your health care provider for more information and advice.

For my Personal Guide to Pregnancy, and other downloads, click here.

For HealthyWomen's due date calculator, click here.

This blog originally appeared on Nurse Barb's Daily Dose. Barb Dehn is a women's health nurse practitioner, award-winning author and nationally recognized health expert. She practices with Women Physicians in the Silicon Valley of California.

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