Week 1 of Your Pregnancy

It's week one of your pregnancy, but the funny thing is that you're not actually pregnant yet. That's right: pregnancy is counted from the first day of the last menstrual period before you conceive. That means that, during week one of pregnancy, no conception has taken place. But even though you aren't pregnant yet, your body is already starting the process of ovulation—and preparing the uterine lining.

Soon after menstruation begins, the body releases a hormone called the follicle stimulating hormone, or FSH. FSH tells your ovaries to start maturing a few follicles in each ovary. One of these follicles will win the race and be released from your ovum during ovulation. Four to seven days after your period begins, hormones send a signal to your body to start the process of thickening the lining of your uterus, to prepare for a fertilized egg. And, in approximately two weeks, a mature egg will be released from your ovaries. At this point, conception may occur.

If you've come here because you just missed your period and/or got a positive pregnancy test, you are likely further along than you think. By the time you get a positive pregnancy test, you are actually about four weeks pregnant. Feel free to skip ahead—and learn more.

Your Unborn Baby's Size at 1 Week

During your first week of pregnancy, you haven’t actually conceived yet. This means there is no fetal growth. But your body is undergoing changes that may soon make conception a reality.

Pregnancy Symptoms Week 1

During week one of pregnancy, you aren't experiencing any pregnancy symptoms. But this is the week you have your period, and you likely are experiencing plenty of symptoms related to that.

Here are some common period facts and symptoms:

• The length of a typical menstrual cycle can last between 24 and 38 days, with about 28 days being the average length.
• Most people bleed between two and seven days, with the heaviest bleeding happening in the first three days.
• Menstrual bleeding can be heavy at times, but you shouldn't be soaking more than one pad or tampon per hour or two.
• Premenstrual syndrome (PMS) is very common and may include moodiness, bloating, headaches, cramping, and sore breasts.

Although period symptoms aren't fun, experiencing symptoms of a normal period is a sign that you have a healthy reproductive system, which can make getting pregnant easier. So what might be some menstrual cycle red flags to watch for as you start trying to conceive?

According to Shaghayegh DeNoble, M.D., OB-GYN and minimally invasive gynecologic surgeon at Advanced Gynecology of North Jersey, there are a few key symptoms to pay attention to. "Irregular bleeding, bleeding very little or heavy, and/or considerable pain during periods can all indicate problems that can interfere with fertility, such as endometriosis, fibroids, or hormonal/endocrine problems," says Dr. DeNoble.

Additionally, you might want to consider the length of your cycle, says Jill Purdie, M.D., an OB-GYN and medical director at Northside Women's Specialists, part of Pediatrix Medical Group, in Cumming, Georgia. "If a person has a period that occurs every two weeks, bleeding that lasts for two weeks or more, or is missing periods, these may all be indicators of a problem that may affect conception," she says.

If you experience any problems during menstruation—or symptoms that concern you—it’s best to reach out to an OB-GYN, midwife, or other health care provider. 

Developmental Milestones

Again, there's no embryo to speak of just yet, but during the week of your period, your body is taking the very first steps toward releasing an egg from your ovary. Looking ahead, some exciting things will be happening and, in a week or two, you might start to notice the signs of ovulation.

You are born with about one to two million egg follicles, and during ovulation—under the orchestration of hormones like FSH, estrogen, and the luteinizing hormone (LH)—your body releases an egg from your ovary. Everyone is different, but for most people, the release of the egg (ovulation) happens about two weeks after the first day of the menstrual period.

Prenatal Tests and Doctor's Appointments

When you are one week pregnant, you won't be having any pregnancy-related appointments, but now is a good time to have a preconception appointment. "Ideally, everyone would make a preconception counseling appointment," says Dr. Purdie. "The goal of this appointment is to improve maternal and fetal outcomes."

What exactly is done during a preconception appointment? A provider will ask you questions about your current state of health, your medical and surgery history, your vaccination status, your medication usage, and your family history, Dr. Purdie says. You will also get a chance to ask questions about your fertility and set some expectations around conceiving.

Can’t afford a preconception appointment? Here are a few things you may want to start doing. Take a prenatal vitamin, decrease alcohol and caffeine intake, and focus on consuming a healthy diet. Research has suggested that diets high in unsaturated fats, whole grains, vegetables, and fish are associated with improved fertility.

Things You Might Consider This Week

While many are excited by the prospect of pregnancy, conception can take time. In fact, it can take several months—or longer—for success. That said, if you’ve been giving it a go for 12 months (or six, if you’re over the age of 35), the American College of Obstetrics and Gynecology (ACOG) recommends you have an fertility evaluation. This series of tests can help you better understand if there is an underlying issue.

Mallorie Hammond, a mom from Boise, Indiana, who lives with her husband and daughter, shared that it took her five years to get pregnant. Her advice for anyone who is starting their trying to conceive journey is to try to go with the flow. "Try not to have any expectations of what might or might not happen," she says.

And if you end up encountering trouble along the way? Hammond says that surrounding yourself with positive support can make all the difference. "Find or follow people on social media platforms that are dealing with similar issues," she says. "That can help you feel less alone during the process. Confiding in close friends throughout the process helps a lot as well."

Support You May Need This Week

Now's a good time to start to think about charting your menstrual cycle. Charting can be as simple as writing down the first day of your period, and noting how many days of bleeding you are experiencing, along with any other symptoms. As the weeks go on, you start to note the signs of ovulation you are experiencing. Charting your cycle can help you time intercourse around your most fertile days and it can also pinpoint any potential fertility issues you might be experiencing related to your cycle.

Week one is also a great time to take care of your mental health. If you are currently seeing a counselor or therapist, you should talk to them about how you are feeling. (If you don’t yet have one, finding and selecting a practitioner can be helpful.) If you take medications to manage a mental health condition, it’s important you connect with your psychiatrist or medical provider. Some medications, for example, cannot be taken while pregnant. And, if you’ve experienced postpartum depression or another perinatal mood disorder before, now is a good time to discuss what treatment worked (and what didn't) last time—and to come up with a plan, suggests Christine Burke, mom of two and parenting editor at Highlights for Children. "I am so glad I did this ahead of conceiving my second pregnancy because it made all the difference in feeling ready to handle/manage PPD," she shares.

Head over to week two of pregnancy

Watch Baby's Growth