Is this the whole story, really?

"[I]f mothers are availed a convenient and sophisticated device like a smartphone, which facilitates social networking and information seeking, will the pregnancy outcome be affected even under a warming planet?"

An indonesian researcher tried to answer this question by looking at the effects of temperatures and rainfall, daily, during pregnancy on weights of nearly 50,000 births in Indonesia in 2017 to 2019.

He found that:

• prolonged spell of extreme rainfall during pregnancy associates with lower probabilities of normal birth. Temperatures on the other hand are not significant.

Does this picture change when mother’s use of smartphone is considered?

Figure 2 shows the change. The obvious one is this: the difference between the exposures narrows. Whether mothers were exposed to extreme rain or normal rain becomes statistically insignificant.

• Even under the warming planet which exposes all mothers to increasing frequencies of extreme rainfalls, mothers with use of smartphones are giving birth to babies of normal weight with higher probabilities instead of babies with low weight
• mothers without a smarthphone… have lower probabilities of giving birth to babies of normal weight by a somewhat larger percentage point than the difference due to extreme rainfall
• Pregnant mothers with smartphones are more than compensating the risk put on them by extreme rainfall spells, thus reaping handsome digital dividends for safer pregnancies.

Hmm, OK. But is this the WHOLE story?

I have no problems to say I do not get how the jump from the data to the conclusion happen.

Is the mere possession of a smartphone enough to have higher probabilities to give birth of normal weight, because it makes it easier to get and share useful knowledge?

Why couldn’t that difference be something NOT directly related to knowledge and sharing it?

Couldn’t it be that having a smartphone is a mere marker of things like e.g.:

• higher income
• living in a more developed area

that is, of having access to better healthcare, healthier housing and food, and other things like those, that surely facilitate giving birth to healthy babies, even for mothers who use their smartphones just to chat with friends and play Fortnite?

Seriously, I am confused. I must be surely miss something, thanks for telling me!