1-4 Weeks Pregnant

When you are 1-4 weeks pregnant you will likely not know for sure if you are pregnant or not. Most women find out when they are due to start their period and it doesn’t start. Then they do a pregnancy test and get their positive result.

Before I discuss what happens when you are 1-4 weeks pregnant, you should be aware that your baby’s due date is calculated using the first day of your last period as a starting point. This is because it is difficult to pinpoint exactly when conception occurred. Once you’ve calculated this you can find out how many weeks along you are.

Use this due date calculator to find out the important dates of your pregnancy.

Due Date Calculator


Due Date Calculator

When was the first day of your last menstrual period?



Number of days in your menstrual cycle
Likely conception date:
End of first trimester (12 weeks):
End of second trimester (27 weeks):
Your due date (40 weeks):
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Using this method, the first two weeks of your pregnancy actually fall before your baby was conceived because they start on the first day of your last period. Your baby will have been conceived roughly two weeks after this point.

At the point of finding out that you are pregnant, if this is when you miss your period and take a pregnancy test, then you will have conceived your baby roughly two to three weeks ago, but you will be four to five weeks pregnant according to the due date calculator.

So, what happens while you are 1–4 weeks pregnant? In the first two weeks, hormones are released from your bloodstream. One of these stimulates the process that results in ovulation, an egg being released from you ovaries.

The other hormone causes the lining of your womb to thicken so that it is ready to receive a fertilized egg.

Of course, during these first two weeks you will have had unprotected sex, and a sperm will have met your egg, (usually in the fallopian tube) and fertilized it. The fertilized egg then continues its journey to the womb and implants itself into the thickened lining.

Once this has happened your cervix gets a little wider and softer and becomes sealed by a thick mucus plug, which protects the uterus from infection.

Also at 1-4 weeks pregnant, after the egg, which starts as a single cell, is fertilized it multiplies into two, then four, then eight cells and continues multiplying. At around day 7 it reaches the uterus and is by now a ball of over 100 cells called a blastocyst and is only about the size of a pin head! It has two layers, the outer one becoming the placenta, and the inner one forms the embryo, which will develop into your precious baby.

The placenta is your baby’s life support system. It allows oxygen, food and protective antibodies to pass from your blood stream, along the umbilical cord, to your baby.

So during this time, if you are trying to conceive then you will likely be feeling excited and impatient about finding out if you are pregnant. You may experience some symptoms that convince you that you are pregnant. (See my page on the early signs of pregnancy to find out what these could be), but you will not know for sure yet.

If you are suspecting you are pregnant, then you will likely be able to take a home pregnancy test when you are about four or five weeks pregnant.

Don’t be disappointed if you are not pregnant, you only have a 20% chance of falling pregnant each month, so just keep trying and stay positive, your time will come soon.

My Second Pregnancy Diary - Weeks 1-4

My husband and I decided we would try for another baby so that Freddy would have a brother or sister by the time he is 2 years old.

Last month was stressful, we tried then as well and when I tested I got a very faint positive line. I was a little confused as to why the line was so faint because last time with Freddy it had been very strong. But after reading countless things online about how even a faint line is still a positive result and that tests vary in their sensitivity I tried not to worry.

After a few days I tested again and the line was still very faint. I couldn’t help worrying. Then another test a day or so later showed a slightly darker line, but still fainter than I thought it should be. That day I also started getting a sharp twinging down in my womb area that persisted throughout the day.

The next day, five days after my positive test result I got the usual period cramps and then bleeding as well. I knew I had lost the baby and a bit of research online revealed that this is called a chemical pregnancy, where the baby is lost very early on, even before some women realise they are pregnant.

After the initial shock and sadness, we decided to get straight on with trying again the next month. And then comes the waiting game again.

With Freddy I hadn’t thought I was pregnant at all. Either inexperience stopped me recognising symptoms or I just barely had any during the 1-4 weeks pregnant time period.

This time I have more of a feeling in these first few weeks before you can do a test. My breasts are a bit bigger, I’ve started feeling a tiny bit of nausea on and off. But the thing that has really made me think is that when I blow my nose I have started to get the odd tiny blood clot on the tissue. This is something I’ve only ever experienced either with a really bad flu or with pregnancy, and since I don’t have even a cold I have a pretty good idea I am probably pregnant.

My worry now is, will I get a strong line when I test? I’ll have to wait and see.

Because my periods are so regular (28 day cycle), I can take a test today, exactly 4 weeks after my last period. I hate the wait before you can test, but I also feel really anxious about getting my result.

I take one of the internet cheapies that I ordered and do the test first thing just after I’ve got Freddy his bottle of milk. My husband is still asleep and unaware of what I’m doing.

I wait…….flush the chain and wash the little tub I just peed into. Then I go back into the bathroom and check the test. BINGO! A clear line.

Davo is pleased, but not surprised, he has great confidence that he can achieve fertilization first time, every time!

I’m relieved to have a stronger line too, which is getting stronger with each test I take. I just did a test and my line was just as strong as the control line. I’m satisfied.

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