Rapid-Fire Reader Questions

Pot, sperm, placentas, reading, and burping?

No COVID today — just your other pregnancy and parenting questions. Enjoy!

Any updated information on pot and sperm counts?

There is continual speculation that marijuana consumption could lower sperm counts or, more generally, impact sperm. It’s not just the number of sperm you have that is relevant. It’s the quality — their shape, how good they are at swimming, etc. There are lots of things that affect sperm. Tight underwear, for example.

In mice, marijuana exposure is linked to infertility. There are biological reasons to think the link might be in people too. There is a 2021 review that pulls together what we know about marijuana consumption and sperm parameters. It does conclude that marijuana is linked to lower sperm counts and worse sperm quality.

However: the evidence is limited. Part of the problem is that sperm quality evaluation isn’t something that people typically do for fun; it usually happens as a result of an evaluation for subfertility or infertility. What the data can show is evidence of a correlation between pot and sperm among a set of people who are experiencing infertility. It’s not clear that this applies in general.

In principle, one could imagine doing an evaluation of this question in healthy men, especially since sperm gets regenerated over time. You could take a cohort of regular marijuana users and encourage a “treatment group” to abstain for a certain period, and measure sperm over time. I am not aware of any studies that have done that. What we can say for now is that the link seems possible and, if you’re struggling with male infertility, it is worth evaluating.

Could you offer data on placenta previa? My doctor says I’m at risk of developing it and wants to put me on bed rest.

Placenta previa is a condition in which the placenta partially or fully covers the cervix. Diagnosis may follow a bleeding event, although in many people it is diagnosed based on a mid-pregnancy ultrasound. 

The major risks with placenta previa relate to bleeding, which can be extremely serious. If you’ve had a bleeding episode with this condition, your doctor will keep a close eye and, depending on the severity, will possibly have you stay in the hospital pre-delivery.

It sounds from your question, though, that what you have is a currently asymptomatic previa diagnosed in mid-pregnancy. The vast majority of cases — perhaps 90% — diagnosed in this way will resolve before delivery. As the fetus grows and the uterus expands, the placenta moves, which can address the issue. So although an estimated 0.3% to 2% of pregnancies do have a placenta previa in the third trimester, which would likely necessitate increased monitoring and a cesarean section, there is an excellent chance that you won’t find yourself in that group.

Even if you do have placenta previa in the third trimester, though, there isn’t any evidence to suggest bed rest will help. I talk about the broader issue of bed rest more in Expecting Better, but the reality is that there are few, if any, conditions for which bed rest is supported in the data. In the case of placenta previa, doctors commonly prescribe “pelvic rest,” which is medical speak for “no sex.” The concern is that putting stuff in your vagina could cause bleeding if the placenta is right at the cervix. This is a logic-based recommendation, but not one with a significant evidence base.

There is also advice to avoid strenuous exercise, heavy lifting, or standing for more than four hours at a time, given small links between these activities and preterm birth in this population. However, no strenuous exercise is not the same as bed rest. Bed rest isn’t part of this recommendation.

There is a challenge of how to approach this with your doctor. There may be factors in your case that lead to their thoughts, and good medical decision-making requires a combination of aggregate data and individual considerations. I think if it were me, I would raise it in the spirit of a genuine question: “Why do you think my case is different from the average?”  

Do you really have to burp babies?

For reasons I do not completely understand, infant burping is a source of a lot of stress and conflict. It’s one of those things that is so ingrained in our platonic ideal of baby behavior that if you do not do it, you’re liable to get an earful from a parent-in-law. On the other hand, it’s easy to find websites that will tell you burping is a scam.  

The underlying argument for burping is that infants may swallow air while they are eating, and burping is a way to clear these air bubbles. The concern is that not doing so could lead to the infant being gassy or colicky or generally fussy. The anti-burpers, though, will tell you that burping might make your infant vomit more. Hard to say!

I checked on this one with Adam Davis, who was my wonderful medical editor on Cribsheet and is a practicing pediatrician. His answer was, basically, that it depends on your baby. First, he emphasized, there is no actual health risk to either burping or not burping. Second, he emphasized that it depends on your baby.

Some babies really seem to need to burp, and if you put them down without doing it, they are fussy. Others couldn’t care less about burping. Why is that? Who knows! Babies are crazy. The message is just to see what works for your baby. There is nothing wrong with giving your baby an opportunity to burp mid-feeding, and similarly you shouldn’t freak out if they don’t burp every time, or ever.

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What do you think of the Doman method for early reading?

Before answering this directly, let me step back on the question of learning to read, which I write about in both Cribsheet and The Family Firm. In Cribsheet, I review evidence on various programs that claim they can teach your infant to read. The evidence does not support these programs! Your baby cannot learn to read. In rare cases, toddlers will pick up reading, though it is uncommon and usually does not result from active teaching. One could begin to teach a kid reading around the age of 3 or 4, although most will not learn until they’re older.

The Family Firm, which deals with school-age kids, looks at data on how kids learn to read. When I dug into that data there — and even more in this interview with the amazing Emily Solari — it’s very clear that the best way to teach kids to read is to focus extensively on phonics. That is: letter sounds, letter combinations, sounding things out. This is as opposed to an approach that emphasizes “whole language”: learning by recognition of words. 

This brings me to your question about the Doman method for babies, which is described in, e.g., this post. In case you do not want to link through, here’s a key takeaway:

First of all, Glenn Doman believes that kids are too smart to bore them with individual letters, phonics and other methods. Over the years of working with children, he discovered that you can teach your child to read in just 90 seconds a day. How? By showing them large whole words a few times a day.

The method effectively encourages the use of flash cards with children as young as, well, birth.  

For all the reasons in the preceding paragraphs, this will not work. Babies cannot read, and phonics is incredibly important. It’s not that you couldn’t get your kid to recognize flash cards! You could (not a baby, but a toddler perhaps). If you show them “CAT” on a card enough times, they’ll recognize the pattern the same way they’d recognize a picture of a cat. But that’s not reading. Reading is if they learn to read CAT and then can read PAT. But pattern recognition doesn’t give you that. Phonics does. 

This isn’t to say, though, that you shouldn’t read with your baby. Reading with your baby is great! It helps them with language and learning to read later, and also it’s something fun to do with a baby if you have nothing else you can think of. Some of my favorite pictures of me with Penelope as an infant are when I’m reading her Moo, Baa, La La La!. Because I am not great with babies, but I do know how to read.  

Bottom line: Read to them because it’s fun. Don’t do flash cards. 

Can you comment on this article, which reports on a study about how babies sleep better if they’re in their own room after four months? 

One of the most contentious things I discuss in Cribsheet is bed- and room-sharing. I’ll put aside bed-sharing for now, which is among the true third rails. But room-sharing can feel nearly as fraught. The American Academy of Pediatrics recommendation has been for infants to be in the parents’ room for at least six months, ideally through a year. The reason is the claim that SIDS rates are lower for infants who are in their parents’ room. 

The evidence for this recommendation is not strong. The studies it relies on are very sensitive to the assumptions made, and they rely on a research design that has problems. Of course, one could make the argument for an abundance of caution in these cases — if there is no downside to room-sharing, then why not do it even if the evidence is somewhat limited?  

One clear reason to consider sleeping apart is to preserve parental sleep. Many parents sleep better if they are in their room alone. Current parenting, though, often seems to dismiss these types of arguments in favor of the sacrifice in all things for your baby attitude. 

This is why I think the study underlying that NPR article is extremely relevant; you can see the full study here. What the authors do is compare child sleep quality for children sleeping in their parents’ rooms or not. They find that four-month-olds who sleep in another room have more consolidated sleep (though sleep for a similar time). At nine months, infants who slept alone slept longer, an effect that was most pronounced for those who were sleeping alone by four months. Perhaps most notably, children who slept away from their parents by nine months were sleeping longer even at the age of 2 and a half.

Is this necessarily causal? No. But it is suggestive, and as evidence it is more compelling than much of the evidence for the increased safety of room-sharing. Does this mean you shouldn’t share a room with your child? Of course not; for many families, that is desirable or a necessity. However, it does offer a counterpoint to the need for this type of room-sharing. Sleeping apart may mean sleeping better, for everyone. 

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