I don't know who my baby's dad is. What can I do?

Rachel Ambler

Consultant midwife

If you're not sure who the dad of your baby is, it's only natural to worry about it all the time. Rest assured you can probably work out who the dad is by looking back at when your last period started.

Now's the time to really focus on your baby and yourself, and be practical. What's done is done, and getting stressed is not good for you or your baby.

So, here's how you can work out who your baby's dad is. You need to know when you were most likely to get pregnant, when you were at your most fertile. If your periods are regular, this should be simple.

First of all, write down when the first day of your last period was. If you don't normally make a note of when your periods start, try to remember other things. Can you remember where you were or what you were doing when your last period started?

Most women have a period every 28 days. If you do too, work out the date your last period started, and count on two weeks. That's when you'll be fertile, because it's around that time that your ovaries release an egg. When your ovaries release an egg, it's called ovulation.

You'll ovulate 14 days before the date your next period is due. So it's an easy calculation to do if you have a 28-day cycle. You'll be fertile half-way through your cycle.

But if your periods come more or less often than 28 days, you'll need to adjust the sums. So, say you have a period every 23 days. Work out the date that your next period was due (the one you've missed) and count back 14 days. On a 23-day cycle, you'll ovulate on day nine.

Once you've worked out when you ovulated, try to remember who you were with around that time. You could have become pregnant if you had sex in the three or four days before you ovulated. Sperm can live inside you for several days, waiting to fertilize your egg when it's released.

You may get more clues about when you conceived your baby when you go for your first ultrasound. You will be offered what's called a dating scan when you're between 10 and 14 weeks pregnant. The scan gives you the first chance to see your baby!

It's called a dating scan because it will work out how pregnant you are and the date when your baby is likely to be born. The date when your baby is likely to be born is called your due date.

Scans are more accurate than counting from the first day of your last period. The person doing the scan, (sonographer) will look at your baby's size. Knowing how big your baby is will make it easier to predict his due date. You can also try using our due date calculator.

Once you know your due date, count back 38 weeks. That will give you the time you got pregnant.

If you were with more than one partner in the space of a few days, it may be difficult to tell for certain who the dad is. If that's the case, although it'll be hard, try not to dwell on it too much during your pregnancy. Tell yourself it'll all be sorted out once your baby is born.

It's bound to be tough going through your pregnancy without sharing it with somebody you know is your baby's dad. Talk to family and friends if you can or talk to your midwife.

Your midwife is there to take care of you, which means she'll want to help you with anything that's upsetting you. Your midwife won't tell anyone else what you've told her. It is often a relief just to talk to someone who did not know you before you became pregnant.

Once your baby is born, you may be so focused on your new arrival that these concerns disappear from your mind. In time, though, you may want your baby's dad to take a share in caring for your baby. And as your child grows, he'll want to know who his dad is.

To get a definite answer about who your baby's dad is, you’ll have to take a paternity test. It's likely to be very important to your boyfriend or former boyfriend to know if he really is your baby’s father.

A paternity test is simple and quick. You, your baby and the assumed dad will each have to give samples of cells taken from inside your cheeks. A quick rub inside both cheeks with a long cotton bud is all it takes.

The cells are checked to see whether the assumed dad shares any genes, or DNA, with your baby. If he does, that means he's the real dad.

You have to pay for a paternity test and the cost of tests is coming down all the time.

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