Home » 24 weeks – first growth scan

24 weeks – first growth scan

This week has involved our first growth scan, and our first meeting with a consultant (as opposed to registrars) at the hospital. It’s also an important milestone to reach in pregnancy, because this is when a foetus is deemed “viable” – a baby born at 24 weeks has a 55% chance of survival, compared to just 15% at 23 weeks (according to Tommy’s).¬†Obviously we want our babies to stay in a lot longer yet, as long as possible, but this is a reassuring milestone to reach.

24 weeks

It is normal for twins to be born slightly earlier than singletons, mainly because their combined size gets to the threshold that the individual mum’s body can cope with sooner and triggers labour. Of course there are other reasons for premature birth of twins too, just as there are for singletons. On average, singleton pregnancies last 39 weeks and twin pregnancies 36 weeks (according to Tommy’s). It would be great if we get to 36 weeks, or even 37/38 weeks as this is classed as “term” for any baby. But there are complications that could arise which could lead to premature birth, either spontaneous premature labour or a decision to end the pregnancy with a c-section due to concern for the babies and/or me. I think I’m more aware of potential complications this time than I was in previous pregnancies, even though I don’t have any risk factors personally other than the fact there are two babies in there instead of one. We are praying that all will be well.

At the other extreme of birth timing from prematurity is what would happen if they didn’t arrive spontaneously by 37 weeks. It was interesting to hear about induction of labour at the antenatal day that Tom and I went to last week. The midwife said that they generally like to start the induction process at 37 weeks for twins, though they would allow me to go until 38 weeks if there were no complications. The biggest risk they perceive is that the placentas stop functioning well enough to support the babies. As both our boys were born spontaneously at 40 weeks (Andrew at 40+4 and Joel on his due date at 40+0), I’m pretty confident that my body is good at timing and will go into spontaneous labour by 38 weeks with twins, providing there are no complications that arise between now and then. So I’m not overly concerned with the supposed “need”¬†for induction.

It was lovely to see the babies again this week, though as they get bigger the clarity of what you can see on the scan is decreasing. They are growing just nicely – pretty much bang on average size for the three measurements taken: head circumference, abdomen circumference and femur (thigh bone) length. The boys were born average weight (7lbs 11oz and 7lbs 9oz) so I expect the twins will be average weight for twins (around 5.5lbs at term). So there are no concerns about them being “too big” or “too small” at the moment, and they are a very similar size to each other (twin 2 is 2% bigger overall).

1st growth scan 1

The way they are both lying (breech) means that their heads are right next to each other currently. The sonographer said it looks like they are plotting something with their heads together!

1st growth scan 2

A lovely little foot from twin 1

They were being very active at the time of the scan, both playing with their cords and limbs whilst the sonographer was trying to measure them. This made it hard to get a good measurement of the blood flow through the cords, so it took a bit longer to scan as she had to come back to this a few different times to eventually get a good enough position with the probe. This sounds entirely accurate for our children – both the boys have always been very active! And I can certainly feel the babies kicking a lot, especially when I’m working at my sewing machines, so they must be able to hear the noise.

As I suspected from the positions of the kicks, both babies are currently in a breech position – bottom down. This is not the position that is favourable for birth, but the sonographer reassured us that there is still plenty of time and space for them to turn to be head down. Usually twins get into their birth position by 32-34 weeks. It’s mainly twin 1 who needs to do this, as twin 2 tends to turn anyway once they have half a womb’s more space to spin about in after the birth of twin 1!

After the scan we had to go to the twins antenatal clinic as usual. First up was the usual blood pressure and urine test. The nurse clearly remembers me now, and tried to make me feel relaxed with various topics of small talk like the weather. It was probably working to some extent, though I couldn’t help feeling she was going a tad over the top, until she told me whilst the machine was measuring my BP that my urine test showed a small amount (1+) of glucose. The BP reading was inevitably high, though I have had higher ones in hospital. So I expected to have to talk both the BP and glucose through with the doctor.

After a short wait, we were called in. This was the first time I got to talk with a consultant, which is standard at 24 weeks in the twins clinic. He was actually more laid back than I expected. He wasn’t at all bothered about the glucose result – he just said a tiny amount like that is neither here nor there at this stage of gestation of twins. He did check that I have a glucose tolerance fasting blood test booked, which I do. I’ve had these even in my singleton pregnancies because my dad is a type 1(.5) diabetic, so I have a risk factor for gestational diabetes, and this time I have two risk factors, the other being twins. I have never had gestational diabetes myself though. So we will see what comes of that test in a couple of weeks.

He also wanted to talk through my BP history and my home monitoring. He agreed that I didn’t currently need to be on the drug to lower BP, and wanted reassurance that I know what I’m doing with testing myself, which I seemed to give him. My monitor reads a bit lower than the static hospital machines, but it did read significantly higher than my home readings last time we did it alongside the hospital ones, so it clearly can detect high BP. Even if I add 10 mm/Hg onto each reading on my machine, they still don’t come out as hypertensive when I’m at home. I told him that I’m a research scientist by training, so he said that I should understand the concept of a fair test with controlled variables, by testing my machine against theirs when I’m in hospital, to check it’s not just my machine reading lower all the time and nothing to do with the fact of being at home. He said to make sure I always bring it with me to appointments, so they can keep checking that it does read higher in hospital, and to call them if I start seeing higher readings at home, which is exactly what I would do, so that’s fine. He was happy to not see me for another 4 weeks, which will be our next growth scan – this is standard for twins. So I’m relieved about that.

So all in all it’s been a good week. I also had a sling consultation to learn how to wrap newborn twins a couple of different ways. I’ll say more about that next week.

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