I jumped down a rabbit hole to try and chase something up. If you want to follow me, take the red pill.
Ok, the WHO report Hammill refers to is here :
http://apps.who.int/gb/fctc/PDF/cop6/FCTC_COP6_10-en.pdf
On the top of page 4 of that report it says :
" (c) The evidence is sufficient to caution children and adolescents, pregnant women, and women of reproductive age about ENDS use because of the potential for fetal and adolescent nicotine exposure to have long-term consequences for brain development.1 "
The 1 at the end is a reference to a Surgeon General's report from 2014, which is here :
http://www.surgeongeneral.gov/library/reports/50-years-of-progress/full-report.pdf (be aware, it's a large pdf and may take a while to load)
The WHO report refers to page 126 of the Surgeon General's report, which is a conclusion that states :
" 3. The evidence is sufficient to infer that nicotine exposure during fetal development, a critical window for brain development, has lasting adverse consequences for brain development. "
The Surgeon General's report bases this claim on a 2011 study, here :
http://pediatrics.aappublications.org/content/early/2011/08/24/peds.2010-3811.full.pdf
This study is based around Swedish snus and the effect they can have during pregnancy. The conclusion states :
" Our study indicates that snuff use during pregnancy is associated with an almost doubled increased risk of neonatal apnea, a finding that is consistent with animal studies of prenatal nicotine exposure. Our results suggest that nicotine is also responsible for these effects in humans, and that alterations in neural programming may be an underlying mechanism. In this perspective, snuff use and NRT should not be regarded as being safer than smoking during pregnancy. "
There is no mention of vaping and the study seems to have been based on topical absorption of nicotine (orally with snus and dermally with nicotine patches). The study conclusion suggests a link with nic (note suggests not absolutely proves) but the conclusions are based on constant topical absorption. Vapers use inhalation in self titrated 'bursts' rather than constant topical absorption.
The study also states that it has weaknesses because it was carried out on neonatal babies, who are more prone to the conditions they were testing for.
It looks like the Surgeon General took the Gunnerbeck study as proof that nic can affect brain development in foetuses. The WHO seem to have latched onto this and tagged vaping in with topical absorption because it suits their agenda.
I'm not an expert, but I think there's a distinct difference between topical absorption and inhalation, particularly when the topical absorption is constant and the inhalation is titrated. (anyone who happens to have forgotten to wear gloves when handling 50mg nic base, accidentally spilled some on their hand and decided they'd finish what they were doing before washing it off could tell you how potent topical absorption can be... ahem
).
The NHS advice on nicotine patches is that they're best avoided during pregnancy but that " use of a 16-hour patch may be appropriate " in some cases :
Who can use nicotine replacement therapy (NRT)? - Health questions - NHS Choices
So, basically the Gunnerbeck study says avoid using snus/nic patches during pregnancy, the Surgeon general extrapolates this to say don't use nicotine at all during pregnancy and the WHO narrows this down to vaping (ENDS) to suit their agenda. Hammill is a lazy hack who couldn't be bothered to research any of this and just parroted the WHO.
In my opinion, this backs up that there is no concrete evidence to suggest that vaping is a danger to unborn foetuses because the original study doesn't offer concrete evidence that nic is the cause of the conditions. It's also based specifically on topical absorption which I believe is more potent than ingestion by inhalation (like I said, I'm no expert but maybe some of our medically minded apes might be able to correct/clarify on this?).
Also, if Hammill was going to use that reference, why did he use it specifically to paint a scaremongering picture re vaping and not nicotine patches/snus? That's what the study used after all.
I'm sure you've seen studies relating to passive vapour and the effects (or lack of) it can have on bystanders, so any inference that it could cause harm to children can be shot down by referencing those. There's a good few references to ETS (that's secondhand tobacco smoke to me and you) in the Surgeon General's report, but quite a few of them show as 'insufficient evidence' and let's not forget, it refers to SHS, not passive vapour, which as we all know has a very much lowered risk profile.
Hope at least some of this helps.